WO2012095785A1

WO2012095785A1 - Systems and methods for inserting support members into the ground

Info

Publication number: WO2012095785A1
Application number: PCT/IB2012/050113
Authority: WO
Inventors: Shmuel Huss
Original assignee: BrightSource Industries Israel Ltd
Current assignee: BrightSource Industries Israel Ltd
Priority date: 2011-01-10
Filing date: 2012-01-10
Publication date: 2012-07-19
Anticipated expiration: 2013-07-10
Also published as: ZA201305623B; US20140000215A1; CN103097612A

Abstract

Support members for heliostats (or other components installed in a field) can be hollow and thin- walled, for example, to reduce construction and/or material costs. However, such support members may be relatively fragile and susceptible to buckling or other damage when driven into relatively rocky and/or hard-packed soil using pile-driving. To avoid damaging the support members, the soil may be pre-conditioned to loosen the soil prior to insertion of the support member therein. An auger can drill a hole in the soil and then be reversed such that soil remains in and/or is subsequently re-introduced into the hole after removal of the auger, thereby leaving a substantially loosened column of soil in the hole. Vibration hammering can cause temporary liquefaction of the soil around the support member to insert the support member into the column of soil while reducing the potential for damage to the support member.

Description

SYSTEMS AND METHODS FOR

INSERTING SUPPORT MEMBERS INTO THE GROUND

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Application No.

61/431,303, filed January 10, 2011, which is incorporated by reference herein in its entirety.

FIELD

The present disclosure relates generally to installation of support elements into the ground, and, more particularly, to methods for installing thin- walled support elements such as heliostat supports into relatively hard and/rocky soil.

SUMMARY

In one or more embodiments, a method for installing a heliostat can include drilling a hole in soil using an auger. A direction of the auger in the hole can then be reversed while removing the auger so as to leave a column of loose soil in the hole. A support member for the heliostat can then be inserted into the column of soil by vibration hammering ("vibro- hammering").

In one or more embodiments, a method for installing a solar energy apparatus can include drilling a hole in soil using an auger. The hole can have a diameter DH. A direction of the auger in the hole can be reversed while removing the auger so as to leave a column of loose soil in said hole. Most of the soil drilled in forming the hole can remain in the hole during the reversing. The method can further include inserting a support member for the solar energy apparatus into the column of soil by vibration hammering. A surrogate object can be used to buttress a circular cross-sectional shape of the support member to prevent bulging or kinking thereof during the inserting. One of a heliostat mirror assembly and a photovoltaic array assembly can then be assembled on the support member. The support member can be a hollow pipe having a maximum outer diameter, Ds, a wall thickness, ts, and a length, Ls. The hole diameter DH can be at least three times the support member diameter Ds. The wall thickness ts can be less than 5% of the support member diameter D_s. The length L_s can be at least 20 times the support member diameter Ds. The support member can have axially and/or radially extending elements arranged so as to resist rotation of the support member about a longitudinal axis thereof once inserted into the column of soil. The support member can have a closed, tapered distal end, which is inserted into the column of loose soil, and an open end that remains above ground after said inserting. The vibration hammering can be such that the loose soil at or near the distal end of the support member undergoes liquefaction as the support member is inserted into said column. The vibration hammering can include applying a reciprocating force in a longitudinal direction of the support member while applying a downward crowd force to the support member via the surrogate object. The surrogate object can include at least one of an insert having an outer diameter closely-conforming to an internal surface of the wall of the hollow pipe, an external support having an inner diameter closely-conforming to an external surface of the wall of the hollow pipe, an internal clamp having radially extending elements for engaging an internal surface of the wall of the hollow pipe, and an external clamp having radially extending elements for engaging an external surface of the wall of the hollow pipe.

In one or more embodiments, a method for installing a solar energy apparatus can include creating a column of loose soil in a hole by using an auger. The hole can have a diameter D_H. Most of the soil in the hole during the creating can remain in the hole. The method can further include inserting a support member for the solar energy apparatus into the column of soil by vibration hammering, and assembling one of a heliostat mirror assembly and a photovoltaic array assembly on the support member. The support member can be a hollow pipe having a maximum outer diameter, D_s, a wall thickness, t_s, and a length, L_s. The hole diameter DH can be at least three times the support member diameter Ds. The wall thickness ts can be less than 5% of the support member diameter D_s. The length L_s can be at least 20 times the support member diameter Ds. The support member can include radially extending elements arranged so as to resist rotation of the support member about a longitudinal axis thereof once inserted into the column of soil. The support member can have a closed, tapered distal end, which is inserted into the column of loose soil, and an open end that remains above ground after said inserting. The vibration hammering can be such that the loose soil at or near the distal end of the support member undergoes liquefaction as the support member is inserted into said column. The vibration hammering can include applying a reciprocating force in a longitudinal direction of the support member while applying a downward crowd force to the support member.

In one or more embodiments, a method for installing a solar energy apparatus can include creating a column of loose soil in a hole by drilling using an auger, and inserting a support member for the solar energy apparatus into the column of loose soil by vibration hammering. The hole can have a diameter D_H. The support member can be a hollow member having a maximum cross-sectional dimension, D_s, and a wall thickness, t_s. The hole diameter D_H can be at least three times the support member cross-sectional dimension D_s. The wall thickness ts can be less than 5% of the support member cross-sectional dimension Ds.

In one or more embodiments, a method for installing a solar energy apparatus can include drilling a hole in soil using an auger. The hole can have a diameter D_H. The method can also include reversing a direction of the auger in the hole while removing the auger so as to leave a column of loose soil in said hole. Most of the soil in the hole from the drilling can be retained in the hole during the reversing. The method can further include inserting a support member for the solar energy apparatus into the column of soil by vibration hammering, and assembling one of a heliostat mirror assembly and a photovoltaic array assembly on the support member. The support member can be a hollow pipe having a maximum outer diameter, D_s, a wall thickness, t_s, and a length, L_s. The wall thickness t_s can be less than 5% of the support member diameter Ds. The length Ls can be at least 20 times the support member diameter Ds. The support member can include radially extending elements arranged so as to resist rotation of the support member about a longitudinal axis thereof once inserted into the column of soil. The support member can have a closed, tapered distal end, which is inserted into the column of loose soil, and an open end that remains above ground after said inserting. The vibration hammering can be such that the loose soil at or near the distal end of the support member undergoes liquefaction as the support member is inserted into said column. The vibration hammering can include applying a reciprocating force in a longitudinal direction of the support member while applying a downward crowd force to the support member.

In one or more embodiments, a method for installing a solar energy apparatus can include drilling a hole in soil using an auger and reversing a direction of the auger in the hole while removing the auger so as to leave a column of loose soil in said hole. The method can further include inserting a support member for the solar energy apparatus into the column of soil by vibration hammering. The support member can be a hollow member having a maximum cross-sectional dimension, Ds, and a wall thickness, ts. The wall thickness ts can be less than 5% of the support member cross-sectional dimension Ds. In one or more embodiments, a method for installing a solar energy apparatus can include creating a column of loose soil in a hole using an auger. The hole can have a diameter DH, most of the soil in the hole during the creating remaining in the hole. The method can further include inserting a support member for the solar energy apparatus into the column of soil by vibration hammering while using a surrogate object to buttress a substantially circular cross- section of the support member during the inserting to prevent bulging or kinking of the support member. The method can also include assembling one of a heliostat mirror assembly and a photovoltaic array assembly on the support member. The support member can be a hollow pipe having a maximum outer diameter, Ds, a wall thickness, ts, and a length, Ls. The wall thickness ts can be less than 5% of the support member diameter Ds. The length Ls can be at least 20 times the support member diameter D_s. The support member can include radially extending elements arranged so as to resist rotation of the support member about a longitudinal axis thereof once inserted into the column of soil. The support member can have a closed, tapered distal end, which is inserted into the column of loose soil, and an open end that remains above ground after said inserting. The vibration hammering can be such that the loose soil at or near the distal end of the support member undergoes liquefaction as the support member is inserted into said column. The vibration hammering can include applying a reciprocating force in a longitudinal direction of the support member while applying a downward crowd force to the support member via the surrogate object. The surrogate object can include at least one of an insert having an outer diameter closely-conforming to an internal surface of the wall of the hollow pipe, an external support having an inner diameter closely-conforming to an external surface of the wall of the hollow pipe, an active insert having radially extending elements for engaging the internal surface of the wall of the hollow pipe, and an active external support having radially extending elements for engaging the external surface of the wall of the hollow pipe.

In one or more embodiments, a method for installing a solar energy apparatus can include creating a column of loose soil in a hole by drilling using an auger, and inserting a support member for the solar energy apparatus into the column of soil by vibration hammering while using a surrogate object to buttress a wall of the support member during the inserting to prevent bulging or kinking thereof. The hole can have a diameter DH. The support member can be a hollow member having a maximum outer cross-sectional dimension, Ds, a wall thickness, t_s, and a length, L_s. The wall thickness can be less than 5% of the support member diameter.

Objects and advantages of embodiments of the disclosed subject matter will become apparent from the following description when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

Embodiments will hereinafter be described with reference to the accompanying drawings, which have not necessarily been drawn to scale. Where applicable, some features have not been illustrated to assist in the illustration and description of underlying features.

Throughout the figures, like reference numerals denote like elements.

FIG. 1 shows a solar power tower system, according to one or more embodiments of the disclosed subject matter.

FIG. 2 shows a solar power tower system with secondary reflector, according to one or more embodiments of the disclosed subject matter.

FIG. 3 shows a solar power tower system including multiple towers, according to one or more embodiments of the disclosed subject matter.

FIG. 4 shows a solar power tower system including multiple receivers in a single tower, according to one or more embodiments of the disclosed subject matter.

FIG. 5A is a side view of a heliostat, according to one or more embodiments of the disclosed subject matter.

FIG. 5B shows a heliostat assembly with a single mirror, according to one or more embodiments of the disclosed subject matter.

FIG. 5C shows a heliostat assembly with a pair of mirrors, according to one or more embodiments of the disclosed subject matter.

FIG. 6A shows a support member inserted into the ground, according to one or more embodiments of the disclosed subject matter.

FIG. 6B shows a cross-sectional view of a support member, according to one or more embodiments of the disclosed subject matter.

FIG. 7 is a flow diagram of a process for installing a support member, according to one or more embodiments of the disclosed subject matter.

FIG. 8A shows an auger drilling a hole during a preconditioning stage of installing a support member, according to one or more embodiments of the disclosed subject matter.

FIG. 8B shows an auger withdrawing from a hole during a preconditioning stage of installing a support member, according to one or more embodiments of the disclosed subject matter.

FIG. 9A shows a support member prior to vibro-hammer insertion into the ground, according to one or more embodiments of the disclosed subject matter.

FIG. 9B shows a support member partially inserted by vibro-hammering into the ground, according to one or more embodiments of the disclosed subject matter. FIG. 10A shows a surrogate object for buttressing the support member during vibro- hammer insertion, according to one or more embodiments of the disclosed subject matter.

FIG. 10B is a close-up of an expansible portion of a surrogate object for buttressing the support member during vibro-hammer insertion, according to one or more embodiments of the disclosed subject matter.

FIG. IOC shows the surrogate object of FIG. 10A inserted into a support member, according to one or more embodiments of the disclosed subject matter.

FIG. 11 A shows a clamping object that buttresses the support member at an open end of the support member during vibro-hammer insertion, according to one or more embodiments of the disclosed subject matter.

FIG. 1 IB shows an external clamp with a passive internal insert for buttressing the support member at an open end thereof during vibro-hammer insertion, according to one or more embodiments of the disclosed subject matter. DETAILED DESCRIPTION

Insolation can be used by a solar tower system to generate solar steam and/or for heating molten salt. In FIG. 1, a solar tower system can include a solar tower 50 that receives reflected focused sunlight 10 from a solar field 60 of heliostats (individual heliostats 70 are illustrated in the left-hand portion of FIG. 1 only). For example, the solar tower 50 can have a height of at least 25 meters, 50 meters, 75 meters, or higher. The heliostats 70 can be aimed at solar energy receiver system 20, for example, a solar energy receiving surface of one or more receivers of system 20. Heliostats 70 can adjust their orientation to track the sun as it moves across the sky, thereby continuing to reflect sunlight onto one or more aiming points associated with the receiver system 20. A solar energy receiver system 20, which can include one or more individual receivers, can be mounted in or on solar tower 50. The solar receivers can be constructed to heat water and/or steam and/or supercritical steam and/or any other type of solar fluid using insolation received from the heliostats. Alternatively or additionally, the target or receiver 20 can include, but is not limited to, a photovoltaic assembly, a steam-generating assembly (or another assembly for heating a solid or fluid), a biological growth assembly for growing biological matter (e.g., for producing a biofuel), or any other target configured to convert focused insolation into useful energy and/or work.

The solar energy receiver system 20 can be arranged at or near the top of tower 50, as shown in FIG. 1. In another embodiment, a secondary reflector 40 can be arranged at or near the top of a tower 50, as shown in FIG. 2. The secondary reflector 40 can thus receive the insolation from the field of heliostats 60 and redirect the insolation (e.g., through reflection) toward a solar energy receiver system 20. The solar energy receiver system 20 can be arranged within the field of heliostats 60, outside of the field of heliostats 60, at or near ground level, at or near the top of another tower 50, above or below reflector 40, or elsewhere.

More than one solar tower 50 can be provided, each with a respective solar energy receiving system thereon, for example, a solar power steam system. The different solar energy receiving systems can have different functionalities. For example, one of the solar energy receiving systems can heat water using the reflected solar radiation to generate steam while another of the solar energy receiving systems can serve to superheat steam using the reflected solar radiation. The multiple solar towers 50 can share a common heliostat field 60 or have respective separate heliostat fields. Some of the heliostats can be constructed and arranged so as to alternatively direct insolation at solar energy receiving systems in different towers. In addition, the heliostats can be configured to direct insolation away from any of the towers, for example, during a dumping condition. As shown in FIG. 3, two solar towers can be provided, each with a respective solar energy receiving system. A first tower 50A has a first solar energy receiving system 20A while a second tower 50B has a second solar energy receiving system 20B. The solar towers 50A, 50B are arranged so as to receive reflected solar radiation from a common field of heliostats 60. At any given time, a heliostat within the field of heliostats 60 can be directed to a solar receiver of any one of the solar towers 50A, 50B. Although only two solar towers with respective solar energy receiving systems are shown in FIG. 3, any number of solar towers and solar energy receiving systems can be employed.

More than one solar receiver can be provided on a solar tower. The multiple solar receivers in combination can form a part of the solar energy receiving system 20. The different solar receivers can have different functionalities. For example, one of the solar receivers can heat water using the reflected solar radiation to generate steam while another of the solar receivers can serve to superheat steam using the reflected solar radiation. The multiple solar receivers can be arranged at different heights on the same tower or at different locations (e.g., different faces, such as a north face, a west face, etc.) on the same tower. Some of the heliostats in field 60 can be constructed and arranged so as to alternatively direct insolation at the different solar receivers. As shown in FIG. 4, two solar receivers can be provided on a single tower 50. The solar energy receiving system 20 thus includes a first solar receiver 21 and a second solar receiver 22. At any given time, a heliostat 70 can be aimed at one or both of the solar receivers, or at none of the receivers. In some use scenarios, the aim of a heliostat 70 can be adjusted so as to move a centroid of the reflected beam projected at the tower 50 from one of the solar receivers (e.g., 21) to the other of the solar receivers (e.g., 22). Although only two solar receivers and a single tower are shown in FIG. 4, any number of solar towers and solar receivers can be employed.

FIG. 5A illustrates an example of a heliostat 70. The heliostat 70 can include a mirror assembly 72. A backing or support layer 74 can hold the mirror assembly 72 to a support member 76, which can be inserted into the ground to hold the mirror assembly 72 in the solar field. The mirror assembly 72 can include a single mirror, as shown in FIG. 5B, or two mirrors, as shown in FIG. 5C. Alternatively, the mirror assembly 72 can include a plurality of mirrors supported by a single support member 76.

Aspects of the disclosed subject matter relate to insertion of support members or elements into the ground. The support members may be used to support heliostat mirror assemblies within a solar field. Alternatively, the support members may be used to hold photovoltaic cells and/or modules (photovoltaic array assemblies) or field instrumentation packages. The support members may be hollow and relatively thin- walled. Such a construction may save on material and/or construction costs; however, this may expose the support member to damage during the installation process, especially when inserting the support member into relatively hard-packed and/or rocky soil, for example, at a desert location. If the support members were directly driven, e.g., via pile-driving, into such ground, the support member would be susceptible to collapse, buckling, and/or kinking. To prevent or at least reduce the risk of damage to the support members, a multi-step insertion method can be used. In particular, the soil can be preconditioned so as to make it susceptible to subsequent vibration induced liquefaction. For example, the ground can be pre-conditioned by augering to form a column of pre-conditioned relatively loose soil. The support member can then be inserted into the preconditioned column of soil by inducing vibrations in the support element using a vibro-hammer.

The support element can be an elongated member 600, as shown in FIGS. 6A-6B. The support member 600 can have a length, L_s, and a maximum cross-sectional dimension (e.g., diameter), D_s. A ratio of the length L_s to the cross-sectional dimension D_s can be at least 5, 10, 15, 20, or more. For example, the support member may be a hollow tube having an outside diameter of 6.7 inches (17 cm) and a length between 11 feet (3.35 m) and 12 feet (3.67 m). The top portion of the support member (e.g., the top 6 inches) can have precision-drilled mounting and/or alignment holes. The support element can be axis- symmetric and/or cylindrical, for example, a cylindrical pylon. The support element 600 can be hollow, such that an interior volume 614 is enclosed by an exterior wall. The exterior wall of the support member 600 can have a thickness, ts. The support member 600 may be considered thin-walled, such that the thickness ts is at most 5%, 4%, 3%, 2%, 1% or less of the cross-sectional dimension Ds. The support member 600 can be constructed from a metal or metal alloy such as, but not limited to, iron or steel. For example, the support member can be a schedule 10 galvanized steel pipe having a 6 inch (15 cm) diameter.

The support member 600 can include surface features to provide resistance against rotational motion of the support member 600 once inserted into the ground 602. For example, the support member 600 can include one or more axially and/or radially extending protrusions, such as fins 612. The fins 612 may be deployed prior to insertion (e.g., permanently installed on a surface of the support member 600) or after insertion (e.g., by deploying from an interior volume of the support member 600 into the surrounding soil in hole 604). Other types of rotation resistance features are also possible according to one or more contemplated

embodiments.

The support member 600 can have a closed end 616 that is inserted into a hole 604 in ground 602 and an open end 618 that remains above ground 602. For example, the support member 600 can be inserted a depth, Li, into a hole 604 in the ground 602, while the open end 618 remains at a height, H, above the ground 602. Height H can be at least 40% of the total length L_s of the support member. The insertion depth Li can be at least 50 cm, 1 m, 1.5 m, 2 m, or more. The hole 604 may be drilled to a depth, L_H, which can be greater than or equal to the insertion depth Li. Because of the relatively fragile nature of the support member 600, the size D_H of the hole (i.e., a diameter of the hole 604) may be larger than needed for the size D_s of the support member 600 (and any surface protrusions 612), so as to reduce the amount of friction or resistance during insertion that may damage the support member 600. For example, a ratio between a depth L_H of the hole (i.e., the preconditioned column) and a cross- sectional dimension D_H of the hole can be on the order of 3, 5, or more. The depth L_H of the hole may be at least 50 cm, 1 m, 1.5 m, 2 m, or more. For example, the depth of the hole may be 3 m.

Referring now to FIG. 7, a method of installing support elements into hard and/or rocky soil is shown. At 702, a location for the support member can be determined. The location may be determined by surveying. For example, a global positioning system based surveying system may be used to accurately determine a location for installation of the support element, for example, for a heliostat within a solar field. After determining the location for the support element, the method can proceed to a pre-conditioning phase at 704.

The pre-conditioning phase 704 can include using an auger to drill a hole for the support element at 706. The drilling in the hole by the auger can serve to loosen and/or pulverize hard soil or rocks in preparation for insertion of the support element therein. FIG. 8A shows an example of an auger 806 drilling a hole 804 in ground 802 resulting in loosened soil region 808. The auger 806 can have flighting that is larger than a diameter of the support member 600 and smaller than an ultimate diameter of the hole 804. For example, the hole may have a diameter D_H that is up to three times the diameter D_s of the support member 600 and up to 50% greater than the auger flighting. In one particular example, the support element has a diameter of 6.7 inches (17 cm), the auger flighting is 14 inches (35.6 cm), and the hole diameter is 21 inches (53.3 cm).

Removing dirt from the site or from the drilled hole can be an issue due to environmental considerations. Accordingly, the loosened dirt 808 may be maintained in or around the hole 804. The method can thus proceed to 708, where the auger 806 is reversed so as to remove the auger 806 from the hole 804, as shown in FIG. 8B. At least some of the drilled dirt may thus be maintained in the hole 804 to form of a column 808 of relatively loose soil. The method can optionally proceed to 710. In some examples, the augering and/or reverse augering can result in some soil in the hole being expelled to a location about ground level. After the augering, a certain fraction of the formed column may be devoid of solid material. For example, soil or other solid particles driven out of the hold during the hole formation may result in void formation in the hole. The void fraction after the augering may be at least 0.1, 0.3, 0.5, 0.7, 0.9, or higher of the volume of the hole. Alternatively or additionally, the void fraction after the augering may be at most 0.9, 0.7, 0.5, 0.3, 0.1, or less of the volume of the hole. At 710, it is possible to re-introduce some or most of the expelled soil into the hole. The loose soil introduced into the hole may serve to fill the void fractions. For example, the introduction of soil into the hole may be effective to refill at least 3%, 5%, 10%, 20%, 25%, 35%, 50%, 75% or more of the voids in the hole. Alternatively or additionally, the loose soil may come from a different source than the drilled hole.

When the hole 804 is filled with soil, it may be filled to ground level 802 or above ground level, as shown in FIG. 8B. The top 810 of the loose soil column 808 can be at ground level 802, above ground level by a height Hp, or below ground level by a depth (not shown). For example, a height H_F of a top 810 of the loose soil column may be above or below ground level 802 by no more than 75%, 50%, 35%, 20%, 10%, 5%, or less of the total depth L_H of the column. Any feature or combination of features relating to a column formed during the augering can also refer to a features relating to a column formed by the combination of augering and re-introduction of soil into locations within the column that may be devoid of soil. The pre- conditioning phase 704 can conclude and proceed to the insertion phase 712.

The insertion phase 712 can include optionally bracing or buttressing walls of the support member with an internal or external clamp at 714. The internal or external clamp may serve to protect the support member from collapse and/or other damage during insertion into the column of dirt. The internal or external clamp may be a surrogate object that transmits force from the vibro-hammer to the support member. An example of a surrogate object 1000 is shown in FIGS. 10A-10B. Elongated surrogate object 1000 may be an elongated expansible insert having a clamping assembly 1004 for coupling the surrogate object 1000 to an interior portion 620 near the distal end 616 of the support member 600, as shown in FIG. IOC. The surrogate object 1000 can be radially inserted into the support member 600 to provide a relatively tight fit so that the support member 600 surrounds the surrogate object 1000 like a sheath. The surrogate object 1000 can be inserted into the interior volume of the support member 600. After insertion, pistons 1002 of the clamping assembly 1004 may extend to push upon the inner wall of the support member 600, thereby attaching and/or clamping the surrogate object to the support element 600. Alternatively or additional, holes or recesses may be provided in an inner surface of the support member wall. Such holes or recesses can receive the pistons for more rigidly coupling the surrogate object to the support member.

Once the surrogate object is engaged to and/or clamped to the support member 600, the vibrating and/or crown force can be transmitted to the support member 600 via the contact between the surrogate object and the interior wall of the support member. With the surrogate member 600 being attached near the distal end 616, the downward/vibrating force acts to pull the support element downward into the hole. The proximal end 618 of the support element 600 can be free to vibrate such that the support element can be inserted into the ground little or substantially no load.

Other types of support and/or force coupling members are also possible according to one or more contemplated embodiments. For example, a clamping member 1100 may be provided at the top open end 618 of the support member 600, as shown in FIG. 11 A. The

downward/vibrating force may thus be applied to the top end to push the support element downward into the hole. The clamping member 1100 may include an insert portion 1104 that fits into the interior volume of the support member 600 and/or exterior portion 1106 that sits adjacent an external surface of the wall of the support member. Although the insert 1104 and the exterior portion 1106 are shown as extending the same length of the support member, this is not to be understood as limiting. Rather, the insert 1104 and exterior portion 1106 may extend different lengths. Thus, the insert 1104 may extend further along the length of the support member 600 than the exterior portion 1106, or vice versa. Either or both of the insert 1104 and the exterior portion 1106 can include pins or pistons 1102, which extend radially from the clamping member 1100 to engage the wall of the support member. The wall of the support member can include one or more holes or recesses for receiving the pistons 1102 of the clamping member for more rigid coupling thereto.

Another configuration for a clamping member 1110 is shown in FIG. 1 IB. Clamping member 1110 can include a passive insert 1114 and an exterior clamping portion 1116. The passive insert 1114 can have an external surface (e.g., diameter) that closely conforms to the interior surface of the wall of the support member 600. The passive insert 1114 can be sized and shaped so as to provide an interference or friction fit at or proximal to the open end 618 of the support member 600. The exterior clamping portion 1116 may have pistons 1102 or other mechanical actuation elements for pressing on the support member exterior wall in order to couple the clamping member 1110 thereto.

In other configurations, passive internal or external surrogate objects may be used to transfer vibro-hammer forces to the support member 600 and/or to support the support member 600 during insertion. The surrogate object can be constructed to conform closely to an interior volume (or a portion thereof) of the support member so as to provide an interference or friction fit between the surrogate object and the support member. For example, the surrogate object may at least partially occupy (or even fully occupy) the internal volume 614 of the support member 600 so as to support the member 600 during insertion.

The method can proceed to 716 where a vibration hammer is used to insert the support member into the loose-soil-filled hole. The support member can be driven into the ground by a combination of a reciprocating force in a longitudinal direction of the support member (i.e., substantially vertical vibrations) that facilitates the liquefaction of the soil and a downward crowd force. The vibro-hammer can provide both the reciprocating and crowd force.

Alternatively or additionally, the vibro-hammer can provide the vibrations while another force- producing machine can provide the downward crowd force.

For example, as shown in FIG. 9A, a vibro-hammer 902 (or an ultrasonic device) can drive a support member 600 into the preconditioned column 808 of soil in the hole 804 in the ground. The vibro-hammer can produce vibrations of a magnitude of at least 5kN, lOkN, 20kN, 30kN, or higher. Alternatively or additionally, the vibro-hammer can produce vibrations of a magnitude less than lOOOkN, 500kN, lOOkN, or less. For example, the vibro-hammer can produce vibrations having a magnitude of 60kN. In another example, the vibro-hammer produces vibrations having a magnitude of 600kN. In particular, the vibro-hammering can cause liquefaction of the preconditioned soil within the column. As used herein, liquefaction refers to the mechanics of soil under monotonic, cyclic, or shock loading whereby the soil loses a proportion of its shear resistance and temporarily flows like a liquid. The liquefaction can allow the support member to be inserted into the preconditioned column of soil in the hole while minimizing or at least reducing the likelihood of damage. The liquefaction may occur at the or near the distal end 616 of the support member 600.

Upon cessation of vibro-hammer activity and the accompanying drop in shear stresses acting upon the soil, the post-liquefaction soil may be compacted about the distal end of the support element so as to effectively secure the support element's position. For example, as shown in FIG. 6A, the soil in the hole 604 can have one or more relatively loose soil regions 606, 608 near the top of the hole 604. The soil in region 610 at the distal end 616 of the support member 600 may be compacted due to soil fluidization and/or volume taken by the support member.

The method can then proceed to 718 where the internal or external clamp can be removed from the support member inserted in the ground. The surrogate object 1000 and/or clamping member 1100 can be removed from the support member 600. For example, the surrogate object 1000 can be pulled upwards after optionally disengaging pistons 1002 from the axial cavity within support member 600. The surrogate object 1000 can thus be reused in inserting another support member 600 at another location. At 720, a heliostat assembly or other desired assembly can be mounted to the support member.

In one or more embodiments, a method of installing support elements into a ground (e.g., including but not limited to hard and/or rocky ground) can include (a) preconditioning a column of ground into loosened soil, and (b) inserting a support element into the preconditioned column of soil using a vibro-hammer. In some embodiments, the support element includes a tapered distal end. In some embodiments, the support element includes a tapered distal end that is substantially sealed to soil so that soil does not enter into the elongated hollow inner cavity of the support element from the distal end as the support element is inserted. In some

embodiments, a hollow cavity of the support element is kept substantially free from soil during the entire insertion process.

In some embodiments, vibrations of the vibro-hammer induce temporary soil

liquefaction. In some embodiments, vibrations of the vibro-hammer induce temporary soil liquefaction at a distal end of the support element. In some embodiments, the support element is inserted to a depth Li. The method may be carried out without causing buckling or breakage or other significant collateral damage of the support element. The support element may be relatively fragile relative to the hard and/or rocky soil before the pre-conditioning so that insertion of the relatively fragile support element in a naked state to the depth Li without the preconditioning would cause buckling or breakage or other significant collateral damage.

In some embodiments, the support element is a steel support element having relatively thin walls whose thickness is at most 5%, 4%, 3%, 2%, 1% or less of the cross section dimension (e.g., diameter) of the support element. In some embodiments, the preconditioning includes augering undisturbed soil. In some embodiments, the preconditioning includes (i) inserting an auger tool into the soil by rotating the auger tool (e.g., a drill bit) in one direction, and (ii) removing the auger tool from the soil by rotating the auger tool in the opposite direction. In some embodiments, the support element is substantially sealed at the distal end so that the support element inserting of step (b) creates a hollow column substantially devoid of soil within the support element.

In some embodiments, the vibro-hammer induces mechanical vibrations within the support element to vibrate at a magnitude that is at least 20 kN and/or at most 100 kN. In some embodiments, the vibro-hammer is configured to induce vibrations within the support element via a surrogate object that is clamped to the support element. In some embodiments, the surrogate object is clamped to the support element at a distal end of the support element (i.e., the end inserted into the ground) without significant clamping at the proximal end of the support element (i.e., the end remaining above ground). In some embodiments, the vibro-hammer is configured to induce vibrations within the support element by direct contact with the support element. In some embodiments, the method further comprises reversibly inserting a re- enforcing non-surrogate elongated object within an interior of the support element during or before the insertion and removing the re-enforcing non-surrogate elongated object from the interior support element after the insertion.

In some embodiments, the method is carried out a plurality of times to hard and/or rocky soil having different local hardnesses and/or rockinesses so that a hardness of each preconditioned column of soil is substantially the same but less than that of the soil outside of each column. In some embodiments, the plurality of times is at least 100 times at a single construction site.

In some embodiments, a method can include (a) creating a column of soil possessing mechanical properties that are different from the properties of a surrounding native soil, and (b) inserting a support element into the preconditioned column of soil, including applying a mechanical energy to the support element. In some embodiments, the mechanical energy includes vibration. In some embodiments, the mechanical energy is effective to produce liquefaction of the column of soil. In some embodiments, the inserting in combination with the column of soil properties is effective to guide the support element along the shape of the column. In some embodiments, the creating includes augering undisturbed soil. In some embodiments, the support element has walls that are too thin to be hammered into the soil without collapsing, buckling, kinking, and/or other damage to the support element. In some embodiments, the support element has a tapered tip at the inserted end.

In some embodiments, the inserting including mechanically engaging side walls of the support element at a lower end thereof. In some embodiments, the support element walls are substantially sealed at the support element lower end. In some embodiments, the method further includes providing the support element with a sealing element having a tapered tip whose walls are thicker than the support element walls. In some embodiments, the creating includes threading an auger into the native soil and reversing the threading to remove the auger. The threading and unthreading may be effective to disrupt the soil without transporting it upwardly. In some embodiments, the inserting is effective to displace soil of the column and transport it upwardly.

In some embodiments, the native soil is harder than the column. In some embodiments, the support element is hollow. The inserting can include inserting a support core into the support element. The core can have expanding elements that expand against the wall of the support element internally to engage the support element. In some embodiments, the support element has a sealing element with a tapered tip whose walls are thicker than the support element walls and the support core extends to the tapered tip and directly supports the tip.

Features of the disclosed embodiments can be combined, rearranged, omitted, etc., within the scope of the invention to produce additional embodiments. Furthermore, certain features can sometimes be used to advantage without a corresponding use of other features.

It is thus apparent that there is provided in accordance with the present disclosure, systems and methods for inserting support elements into the ground. Many alternatives, modifications, and variations are enabled by the present disclosure. While specific

embodiments have been shown and described in detail to illustrate the application of the principles of the present invention, it will be understood that the invention can be embodied otherwise without departing from such principles. Accordingly, Applicant intends to embrace all such alternatives, modifications, equivalents, and variations that are within the spirit and scope of the present invention.

Claims

1. A method for installing a solar energy apparatus comprising:

drilling a hole in soil using an auger, the hole having a diameter DH;

reversing a direction of the auger in the hole while removing the auger so as to leave a column of loose soil in said hole, most of the soil drilled in forming the hole remaining in the hole during the reversing;

inserting a support member for the solar energy apparatus into the column of soil by vibration hammering while using a surrogate object to buttress a circular cross-sectional shape of the support member to prevent bulging or kinking thereof during the inserting; and

assembling one of a heliostat mirror assembly and a photovoltaic array assembly on the support member,

wherein the support member is a hollow pipe having a maximum outer diameter, D_s, a wall thickness, ts, and a length, Ls,

the hole diameter DH is at least three times the support member diameter Ds,

the wall thickness t_s is less than 5% of the support member diameter D_s,

the length L_s is at least 20 times the support member diameter D_s,

the support member includes radially extending elements arranged so as to resist rotation of the support member about a longitudinal axis thereof once inserted into the column of soil, the support member has a closed, tapered distal end, which is inserted into the column of loose soil, and an open end that remains above ground after said inserting,

the vibration hammering is such that the loose soil at or near the distal end of the support member undergoes liquefaction as the support member is inserted into said column,

the vibration hammering includes applying a reciprocating force in a longitudinal direction of the support member while applying a downward crowd force to the support member via the surrogate object, and

the surrogate object includes at least one of:

an insert having an outer diameter closely-conforming to an internal surface of the wall of the hollow pipe;

an external support having an inner diameter closely-conforming to an external surface of the wall of the hollow pipe;

an internal clamp having radially extending elements for engaging an internal surface of the wall of the hollow pipe; and

an external clamp having radially extending elements for engaging an external surface of the wall of the hollow pipe.

2. The method of claim 1, wherein the auger has a flighting that is at least twice the support member diameter.

3. The method of claim 1, wherein the surrogate object includes the insert and the external clamp, both of which are disposed proximal to the support member open end.

4. The method of claim 1, wherein at least 40% of the length L_s remains above ground after the inserting.

5. The method of claim 1, wherein at least some soil is expelled from the hole during the drilling.

6. The method of claim 5, further comprising, after the reversing and before the inserting, re- introducing the expelled soil into the hole.

7. The method of claim 1, wherein a depth of the hole is at least 2 meters.

8. The method of claim 1, wherein after the reversing at least some of the hole is devoid of solid material.

9. The method of claim 1, further comprising, after the inserting and before the assembling, removing the surrogate object from the interior volume of the support member.

10. The method of claim 1, wherein the surrogate object is an insert that fits into an interior volume of the support member and transmits force to the support member wall interior surface via an interference or friction fit.

11. The method of claim 1, wherein the surrogate object is an internal clamp with radially extending pistons that engage corresponding recesses or openings in an interior surface of the support member wall.

12. The method of claim 1, wherein the interior surface of the support member wall is threaded and the surrogate object is an insert that screws into the support member via said interior surface threads.

13. A method for installing a solar energy apparatus comprising:

creating a column of loose soil in a hole by using an auger, the hole having a diameter D_H, most of the soil in the hole during the creating remaining in the hole;

inserting a support member for the solar energy apparatus into the column of soil by vibration hammering; and

the hole diameter DH is at least three times the support member diameter Ds,

the wall thickness t_s is less than 5% of the support member diameter D_s, the length L_s is at least 20 times the support member diameter D_s,

the vibration hammering is such that the loose soil at or near the distal end of the support member undergoes liquefaction as the support member is inserted into said column, and

the vibration hammering includes applying a reciprocating force in a longitudinal direction of the support member while applying a downward crowd force to the support member.

14. The method of claim 13, wherein the auger has a flighting that is at least twice the support member diameter.

15. The method of claim 13, wherein at least 40% of the length L_s of the support member remains above ground after the inserting.

16. The method of claim 13, wherein the support member is a metal or metal alloy.

17. The method of claim 13, wherein a depth of the hole is at least 2 meters.

18. A method for installing a solar energy apparatus comprising:

creating a column of loose soil in a hole by drilling using an auger, the hole having a diameter D_H; and

inserting a support member for the solar energy apparatus into the column of loose soil by vibration hammering,

wherein the support member is a hollow member having a maximum cross-sectional dimension, D_s, and a wall thickness, t_s,

the hole diameter D_H is at least three times the support member cross-sectional dimension Ds, and

the wall thickness t_s is less than 5% of the support member cross- sectional dimension D_s.

19. The method of claim 18, further comprising, after the inserting, assembling a heliostat mirror assembly or a photovoltaic array assembly on the support member.

20. The method of claim 18, wherein the support member includes radially extending elements arranged so as to resist rotation of the support member about a longitudinal axis thereof once inserted into the column of soil.

21. The method of claim 18, wherein, during the inserting, the support member is clamped so as to buttress a wall of the support member from an interior side and/or exterior side of the support member.

22. The method of claim 18, wherein the vibration hammering is such that the loose soil at or near a distal end of the support member undergoes liquefaction as the support member is inserted into the column.

23. The method of claim 18, wherein the vibration hammering includes applying a reciprocating force in a longitudinal direction of the support member while applying a downward crowd force to the support member via surrogate object in contact with an interior wall or an exterior wall of the support member.

24. A method for installing a solar energy apparatus comprising:

drilling a hole in soil using an auger, the hole having a diameter D_H;

reversing a direction of the auger in the hole while removing the auger so as to leave a column of loose soil in said hole, most of the soil in the hole during the drilling remains in the hole during the reversing;

wherein the support member is a hollow pipe having a maximum outer diameter, D_s, a wall thickness, t_s, and a length, L_s,

the wall thickness ts is less than 5% of the support member diameter Ds,

the length Ls is at least 20 times the support member diameter Ds,

25. The method of claim 24, wherein the auger has a flighting that is at least twice the support member diameter.

26. The method of claim 24, wherein at least 40% of the length L_s of the support member remains above ground after the inserting.

27. The method of claim 24, wherein the support member is a metal or metal alloy.

28. The method of claim 24, wherein at least some soil is expelled from the hole during the drilling.

29. The method of claim 28, further comprising, after the reversing and before the inserting, re-introducing the expelled soil into the hole.

30. The method of claim 24, wherein a depth of the hole is at least 2 meters.

31. The method of claim 24, wherein after the reversing at least some of the hole is devoid of solid material.

32. The method of claim 24, wherein at least 10% of the volume of the hole is devoid of solid material.

33. The method of claim 24, wherein the hole diameter D_H is at least three times the support member diameter Ds.

34. A method for installing a solar energy apparatus comprising:

drilling a hole in soil using an auger;

reversing a direction of the auger in the hole while removing the auger so as to leave a column of loose soil in said hole; and

inserting a support member for the solar energy apparatus into the column of soil by vibration hammering,

wherein the support member is a hollow member having a maximum cross-sectional dimension, D_s, and a wall thickness, t_s, and

35. The method of claim 34, wherein the auger has a flighting that is at least twice the support member diameter.

36. The method of claim 34, wherein at least some soil is expelled from the hole during the drilling.

37. The method of claim 36, further comprising, after the reversing and before the inserting, re-introducing the expelled soil into the hole.

38. The method of claim 34, wherein a depth of the hole is at least 2 meters.

39. The method of claim 34, wherein after the reversing at least some of the hole is devoid of solid material.

40. The method of claim 34, wherein at least 10% of the volume of the hole is devoid of solid material.

41. The method of claim 34, wherein the hole diameter DH is at least three times the support member diameter D_S.

42. The method of claim 34, further comprising, after the inserting, assembling a heliostat mirror assembly or a photovoltaic array assembly on the support member.

43. The method of claim 34, wherein, during the inserting, the support member is clamped so as to buttress a wall of the support member from an interior side and/or exterior side of the support member.

44. The method of claim 34, wherein the vibration hammering is such that the loose soil at or near a distal end of the support member undergoes liquefaction as the support member is inserted into the column.

45. The method of claim 34, wherein the vibration hammering includes applying a reciprocating force in a longitudinal direction of the support member while applying a downward crowd force to the support member via a surrogate object in contact with an interior surface or an exterior surface of the support member.

46. A method for installing a solar energy apparatus comprising:

creating a column of loose soil in a hole using an auger, the hole having a diameter D_H, most of the soil in the hole during the creating remaining in the hole;

inserting a support member for the solar energy apparatus into the column of soil by vibration hammering while using a surrogate object to buttress a substantially circular cross- section of the support member during the inserting to prevent bulging or kinking of the support member; and

wherein the support member is a hollow pipe having a maximum outer diameter, Ds, a wall thickness, t_s, and a length, L_s,

the wall thickness t_s is less than 5% of the support member diameter D_s,

the length Ls is at least 20 times the support member diameter Ds,

the vibration hammering includes applying a reciprocating force in a longitudinal direction of the support member while applying a downward crowd force to the support member via the surrogate object,

the surrogate object includes at least one of a:

an insert having an outer diameter closely-conforming to an internal surface of the wall of the hollow pipe; an external support having an inner diameter closely-conforming to an external surface of the wall of the hollow pipe;

an active insert having radially extending elements for engaging the internal surface of the wall of the hollow pipe; and

an active external support having radially extending elements for engaging the external surface of the wall of the hollow pipe.

47. The method of claim 46, wherein at least 40% of the length L_s of the support member remains above ground after the inserting.

48. The method of claim 46, wherein the hole diameter DH is at least three times the support member diameter Ds.

49. The method of claim 46, wherein the surrogate object includes both the insert and the external clamp, both of which are disposed proximal to the support member open end.

50. The method of claim 46, wherein during the inserting, the surrogate object contacts a wall of the support member from an interior side and/or exterior side of the support member.

51. The method of claim 46, further comprising, after the inserting and before the assembling, removing the surrogate object from an interior volume of the support member.

52. The method of claim 46, wherein the surrogate object is an insert that fits into an interior volume of the support member and transmits force to the support member wall interior surface via an interference or friction fit.

53. The method of claim 46, wherein the surrogate object is an internal clamp with radially extending pistons that engage corresponding recesses or openings in an interior surface of the support member wall.

54. The method of claim 46, wherein the interior surface of the support member wall is threaded and the surrogate object is an insert that screws into the support member via said interior surface threads.

55. A method for installing a solar energy apparatus comprising:

inserting a support member for the solar energy apparatus into the column of soil by vibration hammering while using a surrogate object to buttress a wall of the support member during the inserting to prevent bulging or kinking thereof,

wherein the support member is a hollow member having a maximum outer cross-sectional dimension, Ds, a wall thickness, ts, and a length, Ls,

the wall thickness ts is less than 5% of the support member diameter Ds.

56. The method of claim 55, wherein at least 40% of the length L_s of the support member remains above ground after the inserting.

57. The method of claim 55, wherein the hole diameter D_H is at least three times the support member diameter Ds.

58. The method of claim 55, further comprising, after the inserting, assembling a heliostat mirror assembly or a photovoltaic array assembly on the support member.

59. The method of claim 55, wherein the vibration hammering is such that the loose soil at or near a distal end of the support member undergoes liquefaction as the support member is inserted into the column.

60. The method of claim 55, wherein the vibration hammering includes applying a reciprocating force in a longitudinal direction of the support member while applying a downward crowd force to the support member via surrogate object in contact with an interior surface and/or an exterior surface of the wall of the support member.

61. The method of claim 55, wherein the surrogate object is an insert that fits into an interior volume of the support member and transmits force to an interior surface of the support member wall via an interference or friction fit.

62. The method of claim 55, wherein the surrogate object is an internal clamp with radially extending pistons that engage corresponding recesses or openings in an interior surface of the support member wall.

63. The method of claim 55, wherein an interior surface of the support member wall is threaded and the surrogate object is an insert that screws into the support member via said interior surface threads.