WO2012149670A1 - Construction method for root-type foundation anchorage and bored, root-type cast in-situ pile with anchor bolts - Google Patents

Abstract

A construction method for a root-type foundation anchorage comprises the following steps: concrete precasting a bore hole (1) in sections, reserving in the wall of said bore hole (1) holes (3) for the insertion of anchor bolts (2); cleaning the bottom of the bore hole (1), and sealing same with concrete; precasting the cylindrical anchor bolts (2) and, within the bore hole (1), forcing said anchor bolts (2) into the earth (4); sealing a cover over the bore hole (1) to form a flat bearing platform, which can be used as the bearing platform of a pylon foundation. A construction method for a bored, root-type cast in-situ pile with anchor bolts is provided. Use of the rooting-bolt structure increases friction and structural stability.

Description

 Root foundation anchor construction method and root key type bored pile construction method

 The invention relates to a foundation construction method in civil engineering, bridge house construction and hydraulic structure, in particular to a foundation sinking foundation construction method.

Background technique

 At present, the foundations commonly used in engineering construction at home and abroad are: pile foundation, pipe column foundation, sinking foundation, underground continuous wall foundation.

 The pile foundation is the foundation of a pile that is driven into or sinking into the soil and a platform that connects the top of the pile. The external force is distributed to each pile head through the cap, and the force is transmitted to the surrounding soil and the deep soil at the pile end through the pile body and the pile end. The pile foundation is suitable for deep soil. Among all the deep foundations, its structure is the lightest, the degree of construction mechanization is high, and the construction progress is fast, which is a more economical infrastructure. Some bridge foundations are subject to large horizontal forces. For example, the foundation of the pier must withstand horizontal loads from the left and right direction. The pile foundations are mostly bi-directionally inclined piles. The abutments of some beam bridges mainly bear the earth pressure from one side. Tilt to the pile. If the pile diameter is large, like the large-diameter bored piles that are commonly used nowadays, with considerable rigidity, vertical pile foundations can be made without oblique piles. At present, pile foundations commonly used in engineering include prefabricated piles, ordinary cast-in-place piles, immersed tube-filled piles, artificial hole-forming piles, mud-filled piles, etc., which have different shortcomings in use. For example, prefabricated piles will produce noise pollution when hammered, and need to be configured with more steel bars, which is expensive. The amount of steel bars and cement used in ordinary cast-in-place piles is large, and the pile-deep soil is difficult to handle, and the pile body may have shrinkage. The immersed tube cast-in-place pile will generate noise, and it is also prone to pile quality problems, and the bearing capacity is low, and there are many accidents.

 The pipe column foundation is a basic structure consisting of reinforced concrete, prestressed concrete or steel pipe column groups and reinforced concrete caps. The tubular column foundation is also based on a single large tubular column. It is a deep foundation, mostly used for bridges. The pipe string is buried in the soil to a certain depth. The bottom of the column falls as far as possible in the solid soil or anchored in the rock layer. The reinforced concrete cap on the top, the support pier (set) and The superstructure, the total load acting on the cap, is transmitted through the string to the deep dense soil or rock formation. The pipe string is a steel, reinforced concrete or prestressed concrete short pipe joint prefabricated at the factory or on the construction site. It is lengthened at the construction site, forced to sink into the soil by vibration or torsion, and drilled, dug or suctioned in the pipe. To reduce the sinking resistance. If the pipe string falls on the bedrock, the pipe wall can be used as a casing to drill the rock, and the reinforced concrete can be filled to anchor the pipe column to the bedrock to increase the foundation stability and support capacity. It is also necessary to first drill a large diameter hole in the formation, and then insert the prefabricated pipe string into the hole, and press the cement mortar between the column wall and the hole wall to make the pipe column and the soil body tightly connected to improve the bearing capacity. The column can be filled with concrete or reinforced concrete, or even partially hollow. Column foundation: The column foundation is only suitable for riverbeds with no cover or deep cover, and is not suitable for areas with geological defects.

The sinking foundation is a deep foundation in which the caisson is used as the basic structure to transfer the upper load to the foundation. Shenjing is a A bottomless and uncovered wellbore, generally consisting of a blade foot, a well wall, a partition wall, and the like. After digging the soil in the sinking well to sink it, after reaching the design elevation, the concrete is sealed, filled, and the top cover is built to form the foundation of the sinking well. Large buried depth, good integrity, good stability, large bearing area, and can withstand large vertical and horizontal loads. In addition, the sinking well is not only the foundation, but also the retaining and retaining water cofferdam structure during construction. The construction process is simple, the technology is stable and reliable, no special professional equipment is needed, and the compensatory foundation can be made to avoid excessive settlement. Deep foundation or underground structures are widely used, such as bridge pier foundations, underground pump houses, pools, oil depots, mine shafts, large equipment foundations, high-rise and super high-rise building foundations. The sinking foundation: The sinking well is both the foundation and the retaining and retaining structure during construction. It is not necessary to provide pit wall support or sheet pile surrounding wall during the sinking process, which simplifies the construction. However, the construction period of the sinking foundation is long, and the construction technology is highly demanded. Moreover, it is easy to cause sand leakage or sinking difficulty during the construction process.

 The underground continuous wall foundation utilizes various trenching machines to excavate narrow and deep trenches in the ground by means of the protective effect of the mud, and to cast appropriate materials into them to form an anti-seepage (water) and retaining soil. And continuous underground walls with load-bearing functions. The underground continuous wall construction has small vibration, low noise, large wall rigidity, good anti-seepage performance, and no disturbance to the surrounding foundation. It can form an arbitrary polygonal continuous wall with great bearing capacity to replace the pile foundation, sinking foundation or caisson foundation. The soil can be adapted to a wide range of areas, including weak alluvium, medium hard formations, dense gravel layers, and rock foundations. Initially used for dam body seepage prevention, reservoir underground interception, and later developed into part or all of the retaining wall and underground structure. The deep basement, underground parking lot, underground street, underground railway, underground warehouse, mine, etc. of the house can be applied. Underground continuous wall foundation: This kind of foundation is under some special geological conditions (such as very soft silty soil, alluvial layer containing boulders and super-hard rock, etc.), which is very difficult to construct, and if the construction method is improper or construction geology The conditions are special, and there may be problems in that adjacent wall segments cannot be aligned and leak. In addition, underground continuous walls are more expensive than other methods if used as temporary retaining structures. When the city is constructed, the disposal of the waste mud is troublesome.

Summary of the invention

 OBJECT OF THE INVENTION The technical problem to be solved by the present invention is to provide technical problems such as difficulty in foundation making, high requirements for foundation treatment, high technical requirements, and high risk in the prior art foundation construction process, providing simple process, low consumption, and quick construction. , safe and reliable root sinking foundation construction method.

 In order to solve the above technical problem, the present invention discloses a root foundation anchor construction method, which comprises the following steps:

The concrete section is prefabricated into a sinking well, and a root key hole for inserting a root key is reserved on the wall of the sinking well, and the sinking well is sunk into the soil by its own weight, and the sinking bottom stops when the bottom of the sinking hole hits the rock, One end of the root key is pointed and the other end is flat; in the sinking well, the bottom is cleared, and the concrete is used to form the back cover; Prefabricated rod-shaped concrete roots, which are topped into the soil in the sinking well;

 A flat-shaped cap is formed on the surface of the sinking well, and a flat cap is used as the base of the pier.

 In the present invention, it is further preferred that the preformed bar-shaped concrete roots, the topping of the roots into the soil in the sinking well comprises the following steps:

 a vertical slideway is arranged on the inner wall of the caisson, and the vertical slideway and the sinking well are fixed by the track anchor;

 a diagonal bracing is arranged on the inner wall of the chute, and an annular rail beam is arranged on the diagonal bracing of the same section;

 a jacking platform is arranged on the circular track beam, and a supporting steel bar is arranged on the jacking platform;

 The root key is placed on the jacking platform, the tip end of the root key is aligned with the root key hole, and the other end is pushed by the jack to push the root key into the soil.

 In the invention, in the process of pushing the root key by using the jack, the crane is used to hang the root key, and the root key is used to ensure that the root key is inserted into the soil according to the design direction.

 In the present invention, a water stopping rubber and a water retaining rubber sheet are sequentially disposed in the root key hole; a cross-shaped opening is formed in a middle portion of the water stopping rubber, and one end of the root key tip is sequentially inserted into the water stopping rubber and the water retaining rubber board. Since the inner size of the rubber water stop plate is smaller than the outer size of the top tube, when the root key is pushed into the incision, the rubber sheet is bent outside the well and tightly wrapped around the outer wall of the root key, thereby functioning as a dynamic seal to stop the water.

 In the present invention, a sealing steel plate is installed at an outer wall of the root key hole on the wall of the caulking; a pre-cracking line is provided on the sealing steel plate along a diagonal line. If the water-stopping rubber and the water-repellent rubber sheet are installed, insert the sealing layer in the thickness of the root key and seal the sealing steel plate.

 In the present invention, a grouting hole is provided in the outer edge of the root key hole.

 The invention also discloses a root key type bored pile construction method, comprising the following steps:

 The steel cage is placed in the pile hole; the steel cage includes an outer main rib and an inner main rib, and a guiding skeleton is welded between the outer main rib and the inner main rib, and the guiding skeleton is formed by welding two or more steel bars to the guiding rings at both ends, and guiding The skeleton is evenly arranged in the circumferential direction in the outer main rib and the inner main rib, and the guiding skeleton is arranged from top to bottom along the axis direction of the outer main rib and the inner main rib, and each guiding skeleton is inclined above the horizontal plane to facilitate extrusion and expansion; The outer main rib and the inner main rib are fixed by the stirrup;

 Each of the guiding skeletons is provided with a root key, the front end of the root key is pointed and conical, and the end is a smooth circular arc surface; the steel cage is squeezed and expanded by using a vibration squeezing device; Head, connecting rod and static pressure vibration device;

Squeeze and expand the extrusion head from top to bottom, and after all the roots are squeezed into place, the extrusion head is proposed to cast the cast-in-situ concrete, and the casting of the guided skeleton concrete is ensured when the vibration is guided, and the skeleton is formed into a root. Key anchor Strengthen the point.

 In the above method of the present invention, the height of the squeezing head circular table is between one and two times the distance between the upper and lower guiding frames, and the upper row of the roots is squeezed by the squeezing head while the lower row of the squeezing heads is squeezed. It will be guaranteed to stabilize.

 In the above method of the present invention, a geotextile or a sleeve is arranged on the outer side of the steel cage, and a geotextile or a sleeve is pre-set in the position of the corresponding steel cage according to the construction drilling record, and both of them should ensure the protective layer of the main reinforcement. thickness.

 The principle of the invention is as follows: The root sinking foundation is to use the sinking hole to reserve the pushing hole, and after the sinking sinks to the design elevation, the prefabricated root key is pushed in the soil body, after ensuring the consolidation of the root key and the sinking well Form a biomimetic basis. The root sinking foundation can improve the horizontal and vertical bearing capacity of the bridge foundation, and can well meet the stability requirements of the foundation's self-settlement, anti-sliding, anti-pulling and anti-overturning. In terms of material stiffness combination, the root caisson foundation is a combination of rigid body (sinking well), finite stiffness beam (root bond), elastoplastic body (soil body), and the finite stiffness beam provides a good stiffness transition and Stress distribution transfer effect. At the same time, the foundation of the form can be structurally designed for the caps, anchors and saddles (sets), and the overall optimization can be carried out by means of anchor cable divergence and reduction of the pulling force arm, so as to maximize the soil. Resistance. In addition, the foundation of the root-type caisson breaks through the traditional anchoring foundation and relies solely on the mechanism of the friction of the base and the basement. The foundation beam effect of the foundation root is fully dispatched, and the deep overburden is simplified by the method of “normalization to zero”. The difficulty of foundation construction has increased the prefabrication of the construction, and the quality of the deep foundation has been controlled.

 Advantageous Effects: The present invention greatly optimizes the conventional infrastructure, and greatly enhances the friction by adopting a root-bond structure; and increases the stability of the structure by utilizing the gripping force of the soil on the root bond, Small structure gravity provides the possibility to have better economy; the root foundation process is simple, the construction is fast, safe and reliable; its structural form and construction method can be widely applied to horizontal hydraulic and vertical structures such as bridges. In the case of pressure combined forces, it can also be extended to the basis of the corresponding large structure.

DRAWINGS

 The above and/or other aspects of the present invention will become more apparent from the detailed description of the invention.

Fig. 1 is a schematic view showing the construction of a root type foundation anchor in the present invention.

2 is a schematic view showing the structure of a root keyhole in the present invention.

Figure 3 is a schematic plan view of the structure of Figure 1.

Fig. 4 is a schematic view showing the construction of the water-stopping rubber and the water-blocking rubber sheet in the method of Fig. 1.

Figure 5 is a schematic view showing the structure of the water-stopping rubber of the present invention.

Fig. 6 is a schematic view showing the construction method of the root-key type bored pile in the present invention.

detailed description

As shown in FIG. 1 and FIG. 3, the present invention discloses a root foundation anchor construction method, which comprises the following steps: The concrete section is prefabricated into the sinking well 1. The inner wall of the caisson is reserved for the root keyhole 3 for inserting the root key 2, and the sinking well is sunk into the soil 4 by its own weight, and when the bottom of the caisson hits the rock Stop sinking, the root button has a pointed end at one end and a flat head at the other end;

 Clearing the bottom in the sinking well and forming the back cover with concrete;

 Prefabricated rod-shaped concrete roots, which are topped into the soil 4 in the sinking well;

 A flat-shaped cap is formed on the surface of the sinking well, and a flat cap is used as the base of the pier.

 The prefabricated rod-shaped concrete root key, which is inserted into the soil in the caisson, comprises the following steps: a vertical slide 5 is arranged on the inner wall of the caisson, and a rail anchor is passed between the vertical slide and the sinking well 6 Fixed; a diagonal bracing 7 is provided on the inner wall of the chute, and an annular rail beam 8 is arranged on the diagonal bracing of the same section;

 a jacking platform is arranged on the circular rail beam, and a supporting steel rod 10 is arranged on the jacking platform;

 The root key is placed on the jacking platform, the tip end of the root key is aligned with the root key hole, and the other end is pushed by the jack to push the root key into the soil.

 During the use of the jack to push the root key, the crane is used to lift the root key to ensure that the root key is pushed into the soil according to the design direction. As shown in Fig. 2, a grouting hole 11 is provided at the outer edge of the root keyhole 3, and a root key 2 is formed in the hole.

 As shown in FIG. 4 and FIG. 5, a water stopping rubber 12 and a water blocking rubber plate 13 are sequentially disposed in the root key hole; a cross-shaped opening 14 is formed in a middle portion of the water stopping rubber, and the root end of the root key is sequentially topped. Into the water rubber and water retaining rubber sheet. The process step at this time is that after the sinking mud sinks and the bottom sealing water is pumped, the water retaining rubber plate acts to block the mud sand outside the sinking well from entering the interior of the sinking well. After the bottom of the well is sealed, the muddy sand remaining in the hole is removed, and the root key and the jack are placed in position to prepare for pushing. The root key blade passes through the water stop rubber. When the blade tip is about to contact the water retaining rubber plate, the water stop rubber has tightly wrapped the root key. At this time, the surrounding water stop rubber is compressed by 1 cm to stop the water. Under the pushing action of the jack, the root key blade penetrates the water retaining rubber plate and pushes forward. When the root key is pushed into position, the water-stop rubber surrounding the root key is compressed by 2 cm, and the outwardly protruding rubber is completely compressed into the connecting groove of the steel jacket. Since the compression amount of the rubber can be more than 25%, the rubber sheet having a width of not less than 6 cm in the joint groove can satisfy the compression requirement. After the root key is pushed into place, the inner and outer steel sleeves are welded together.

 As shown in FIG. 6, a root key type bored pile construction method includes the following steps:

The steel cage is placed in the pile hole; the steel cage includes an outer main rib 15 and an inner main rib 16, the outer main rib 15 and the inner main rib 16 are pile main ribs 17, and the main rib 17 of the pile is provided with lifting ribs 18, the outer main rib and the inner main rib A guiding frame 19 is welded between the guiding frame, and the guiding frame is welded by two or more reinforcing bars 20 at both ends. The guiding frame is evenly arranged in the circumferential direction in the outer main rib and the inner main rib, and the guiding skeleton is along the outer main rib and the inner main rib. The direction of the axis is set from top to bottom, and the horizontal plane of each guiding frame is inclined upwards; the outer main rib and the inner main rib are passed through the stirrup 22 Fixed; place a geotextile or sleeve on the outside of the cage.

 Each of the guiding skeletons is provided with a root key 23, the front end of the root key is pointed and conical, and the end is a smooth circular arc surface; the steel cage is squeezed and expanded by using a vibration squeezing device; Expansion head 24, connecting rod 25 and static pressure vibration device 26;

 Squeeze and expand the extrusion head from top to bottom, and after all the roots are squeezed into place, the extrusion head is proposed to cast the cast-in-situ concrete, and the casting of the guided skeleton concrete is ensured when the vibration is guided, and the skeleton is formed into a root. The anchor of the bond strengthens the point.

 The height of the squeeze head truncated cone is between one and two times the distance between the upper and lower guide frames.

 The present invention provides a method and a method for constructing a root-type caisson foundation. The methods and methods for implementing the technical solution are numerous. The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art will It is to be understood that a number of modifications and refinements may be made without departing from the principles of the invention, and such modifications and refinements are also considered to be within the scope of the invention. The components not specifically defined in this embodiment can be realized by the prior art.

Claims

A root foundation anchor construction method, characterized in that it comprises the following steps:  The concrete section is prefabricated into a sinking well, and a root key hole for inserting a root key is reserved on the wall of the sinking well, and the sinking well is sunk into the soil by its own weight, and the sinking bottom stops when the bottom of the sinking hole hits the rock, One end of the root key is pointed and the other end is flat; in the sinking well, the bottom is cleared, and the concrete is used to form the back cover;  Prefabricated rod-shaped concrete roots, which are topped into the soil in the sinking well;  A flat-shaped cap is formed on the surface of the sinking well, and a flat cap is used as the base of the pier.  2. The root foundation anchor construction method according to claim 1, wherein the preformed rod-shaped concrete root key, the root key is placed in the soil in the sinking well, and comprises the following steps:  a vertical slideway is arranged on the inner wall of the caisson, and the vertical slideway and the sinking well are fixed by the track anchor;  a diagonal bracing is arranged on the inner wall of the chute, and an annular rail beam is arranged on the diagonal bracing of the same section;  a jacking platform is arranged on the circular track beam, and a supporting steel bar is arranged on the jacking platform;  The root key is placed on the jacking platform, the tip end of the root key is aligned with the root key hole, and the other end is pushed by the jack to push the root key into the soil.  3. The root foundation anchor construction method according to claim 2, wherein the jack is used to lift the root key during the pushing of the root key, and the root key is used to ensure that the root key is inserted into the soil according to the design direction.  The method for constructing a root foundation anchor according to claim 1, wherein a water stopping rubber and a water blocking rubber sheet are sequentially disposed in the root key hole;  A middle portion of the water stopping rubber is provided with a cross-shaped opening, and one end of the root key is sequentially inserted into the water stopping rubber and the water blocking rubber plate.  The root type anchor anchor construction method according to claim 1, wherein a grouting hole is provided at an outer edge of the root key hole.  6. A root key type bored pile construction method, characterized in that the method comprises the following steps:  The steel cage is placed in the pile hole; the steel cage includes an outer main rib and an inner main rib, and a guiding skeleton is welded between the outer main rib and the inner main rib, and the guiding skeleton is formed by welding two or more steel bars to the guiding rings at both ends, and guiding The skeleton is evenly arranged in the circumferential direction in the outer main rib and the inner main rib, and the guiding skeleton is arranged from top to bottom along the axis direction of the outer main rib and the inner main rib, and each guiding skeleton is inclined above the horizontal plane; the outer main rib and the inner main rib pass Stirrups fixed; Each of the guiding skeletons is provided with a root key, the front end of the root key is pointed and conical, and the end is a smooth circular arc surface; the steel cage is squeezed and expanded by using a vibration squeezing device; Head, connecting rod and static pressure vibration device; Squeeze and expand the extrusion head from top to bottom, and after all the roots are squeezed into place, the extrusion head is proposed to cast the cast-in-situ concrete, and the casting of the guided skeleton concrete is ensured when the vibration is guided, and the skeleton is formed into a root. The anchor of the bond strengthens the point.  7. The root-bond type bored pile construction method according to claim 6, wherein the height of the diverging head circular table is between one and two times the distance between the upper and lower layers of the guiding skeleton.  8. The root-bond type bored pile construction method according to claim 6, wherein a geotextile or a sleeve is disposed on an outer side of the steel cage.