WO2016055119A1 - Erosion excavator method - Google Patents

Abstract

The invention relates to a method for removing deposits of sand and/or silt from the bottoms of bodies of water, optionally by means of hydropneumatic methods, in particular water injection, suction dredging or the like, in that, optionally prior to the hydropneumatic removal method being used, the sand/silt deposit to be removed is subjected to a force which reduces the viscosity of the deposit, the pressure on the deposit exerted by the devices serving to apply the force being variable.

Description

 Erosional processes excavators

The invention relates to a method and a device for removing stagnant sandy / schiuffige to silty deposits on the bottom surfaces of bodies of water. By means of a mechanical dynamic force, sediments are made more fluid over a large area and can be combined with - or without hydropneumatic

Force effects are better mobilized.

 By the use of natural physical properties that is

Dredging process more environmentally friendly, energy-saving and more efficient than

conventional methods.

In many waters, especially in busy streams, the fairways are to be deepened to allow the navigability of modern container ships. Because of dredging, the (currently already steadily increasing dredging costs) will continue to increase exponentially in the planned wells. From 2007 to 2012, in the Federal Republic of Germany, these increased by approx. 100% to approx. € 150 million in relation to € / m ³ . In this

In addition, costly and expensive dredging work in the adjacent ports is also necessary to enable tide-independent shipping traffic.

Here are the improved environmental protection, the energy and cost savings and

the same special meaning. The invention contributes to the solution of these problems. The dredging method according to the invention can generally be used in combination with the known hydropneumatic methods, such as the suction dredger method or the water injection method, as well as independently.

Suction dredger methods are suitable for almost all types of sediment and have been widely described. Today, such methods are used in which the sucked mixture of solid and liquid components in the hold of the ships is partially separated, so that a portion of the sucked water can be returned to the water (Suction Hopper Dredging).

In the known water injection method, water is injected under pressure into the surface layer of the waterbed to be removed in order to reduce the viscosity of this layer without destroying it by fluidization. The layer thus treated (also referred to as a density layer) may have a suitable level difference on the

Drain water bottom. For a detailed description of water injection methods, see for example Meyer-Nehls in "Die Wasserinjektionsverfahren. Results from the

Dredging Material Investigation Program ", Issue 8, October 2000, FHH Hamburg, ISSN 0177-1191. A recent publication which also deals with injunction proceedings is DE-Al 10 2009 015 203. Injection methods are particularly useful for removing silt and the like deposits.

Dredging with the water injection device (WI-Sprayer) and the hopper dredger are reaching the limits of their performance especially in sandy / low silty sediments, with a linear grain distribution (especially of the sand fraction). By "sandy / silty" in the context of this description is meant the presence of sand together with clay particles.

In principle, in both ("hydropneumatic") method, a rearrangement of the sediments from a partially stable position by water pressure or by water suction. In the water injection process, the sediment is released by means of water pressure of 1, 5 to 3 bar via nozzles from the bottom and rearranged by naturally prevailing gradient or currents.

In the hopper dredger, the sediments with the surrounding water over a

Pumped sucking proboscis by pump suction from the bottom of the ship's hold. There, the transport water is largely separated from the sediments by sedimentation in the hull and returned to the water. The remaining sediments are transported by dredge and either dumped at one point in the water or relocated ashore in rinsing fields.

While in silty (poorly sanded) sediments the rearrangement is done with better results in terms of times of use, in case of special Ilgen Sands the amount of time spent in terms of dredging performance is high and hence the cost is unduly high.

Such sediments with linear grain distribution of silty fine sands often occur in waters due to the naturally occurring longitudinal classification. They are often complicated and more expensive to mobilize with the known, above-mentioned hydropneumati-acting methods.

Due to the longer processing times more suspended matter is generated from the dense streams of the transported sediments, which should be avoided for reasons of water quality.

The required in the excavation with the hopper dredger with the suction organisms are largely mechanically crushed by the pump, which can be seen from the fragments and the foam at the outlet. In addition, the shipping traffic is through unnecessarily extended operating times more than necessary hampered by the dredging, which statistically leads to a greater risk of accidents.

So far known are methods for better mobilization of fine-grained, sandy and / or silty sediments in waters by the thixotropic properties of such sediments are used in the rearrangement. However, this is only small-scale (few dm ² ), while the excavator method according to the invention (depending on the applied hydraulic power) - this is possible in the range of several m ² sediment and thus a much larger area can be achieved by water suction and water pressure.

FR 2 860 532 relates to methods for hydropneumatic removal of deposits i. W. by suction dredging. This is a technique for recovering the dredged material

provided that the sediment to be removed can be loosened by means of a (possibly separate) vibrating device ("aiguilles vibrantes").

However, this proposal relates specifically and expressly not sandy sediments, but deposited silt and clay or clay, so deposits that consist essentially of the smallest particles and have a narrow particle size distribution (below 1 to a maximum of about 100 microns).

DE-OS 2 256 627 discloses a method for removing mud, but not sand. A "vibration effect" takes place here in that the entire cutting head is vibrated.

US 5,146,699 discloses a method for removing toxic sludge, so also not sand. There is no vibratory effect on the sediment here. The apparently comparable devices (vibrator 86, frame 23) instead serve only for lateral movement of the shear device for cutting sediment chunks. The state of the art can be significantly improved in terms of effort and effect. An essential object of the invention is this improvement. The aim is an effective mechanical energy input for all sediment compositions.

To solve this task serve the feature combinations of independent

Claims. The dependent claims define advantageous embodiments.

An essential aspect of the invention is to make variable the printing of the vibrating plate on the sediment surface (for example, by inflatable buoyancy bodies). Thus, the vibrating plate without buoyancy deep into solid fine sands, but at the other extreme with much buoyancy to slide flat over mud surfaces. It can with little energy of

Vibratory plates in almost all sediments, the flowability can be increased. The necessary imprint on the sediment is roughly a few kg / m up to about 250 kg / m and may be e.g. can be easily controlled with inflatable commercial round fenders.

In principle, before the (optional) hydropneumatic action by the

aforementioned dredging method on the sediment, the kinematic and dynamic

Viscosity of the partially stable sediment due to targeted mechanical forces on the thixotropic medium significantly reduced in the short term.

The mechanical force is preferably applied by shearing and shaking on the sediment surface. To optimize the energy use is in the

relocated sediments sought a resonance. The optimal parameters can be easily determined by preliminary tests.

When shaking the pore water in the sediment during the transmission of power into the depth of the sediment layer with. The frequently occurring stabilizing corrugation of the sediment surface is dissolved and the moment of inertia of the recumbent is minimized.

The hydrostatic pressure of the overlying body of water, currents and the influence of the physical boundary layers reduce the energy input in reducing the stability and the inertia of the sediments to be relocated.

In summary, shaking and shearing of thixotropic sediments temporarily and partially reduces their viscosity, which makes it faster and more energy efficient to remove these deposits, which are difficult to remove by conventional excavator techniques.

While it is conceivable to form a device for the application of the invention as a separate device, the technical device for reducing the viscosity is preferably installed on Wasserinj tion excavators, hopper dredgers and tractors. It consists for example of a bar-like lowerable device, which is up to 12 m long and is carried along the direction of travel of the ships resting on the sediment. Through this device, the mechanical energy is transmitted via vibrators, shaving heads, vibrators and eccentrics to the thixotropic sediment. The respective use of the aforementioned various devices depends on the sediment quality to be processed and is selected according to the best efficiency.

The device is z. B. in the water injection method in processing processing direction before, and approximately parallel to, the water injection bar and reduces the viscosity. By means of hydrodynamics, the sediment is injected into the following injector nozzles

Dense current transferred, which is rearranged with the flow or slope. An advantage of this combination method is that, compared to the known WI and Hopper method, significantly more thixotropic sediment per unit time can be mobilized.

According to the invention, the effectiveness of the method is improved by variable pressure of the device on the sediment to be removed during the energy input.

In a particularly preferred embodiment, the vibrating devices, in particular vibrating plates, described in greater detail below and shown in the drawings, serve for this purpose. These are preferably mounted near the suction head or the water injection bar.

The invention will be explained in more detail with reference to the accompanying drawings. Show in it

Fig. 1: A loading space suction dredge according to a first embodiment of the invention;

Fig. 2: A water-injection excavator according to another embodiment of the invention, and

FIGS. 3a-c show details of a preferred embodiment of a vibrating plate according to the invention

Fig. 1 shows a loading space suction dredger 1, which is provided with a suction tube 2. The suction tube 2 carries a suction head 3, which receives sediment from the surface of the water bottom 4. Fig. 2 shows a water injection excavator 5, which is provided with an injection tube 6. The injection tube 6 carries a water injection bar 7, which enters water under pressure in the sediment.

In the vehicles shown in Fig. 1 and 2, 6 vibrating plates 9 according to the invention by means of struts 10 are attached to the suction tube 2 and the injection tube.

Fig. 3 a shows such Rüttelblech 9 in top view. The Rüttelblech is mainly (1 1) flat and has two upwardly inclined metal strips 1 l a, b at its (in the direction of movement) leading or trailing edge. Approximately in the center, a growing area 12 is provided for a vibrator (not shown). Near two opposite side edges are

Means 14 for attachment to a strut (10, see Fig. 1 and 2) are provided.

Fig. 3b shows the same Rüttelblech 9 in view from below. The flat lower major surface 15 rests on the sediment during use. The metal strips 1 la, b (which can be produced by bending the sheet) prevent unwanted penetration into the sediment.

The vibrating plate 9 is provided on the underside with vibration lamellae 16, which penetrate into the sediment.

Fig. 3c shows the Rüttelblech 9 in side view (transverse to the direction of movement).

The Rüttelbleche be fined on the struts 10 from the dredger 1, 2 on the sediment 4,8. It can be provided to adjust the pressure exerted by the Rüttelbleche on the sediment. Via a pathogen, mechanically dynamic pulses are induced in the resonance area in the soil. The Rüttelbleche 9 are in certain, sufficiently large distances in front of the suction head 3 of the hopper dredger or before

Water injection bar of the WI device 5 attached via joints and hydraulic control. A vibrating plate 9 consists in principle of steel plates from ² sizes and a thickness of 8 mm. At the front I Ia and rear II b side of the sheets 9 are folded so that they can slide over the ground. Several of these Rüttelbleche 9 are movably attached to each other and pulled over the sediments at the bottom - up to the width of the working track of the dredgers. The size and thickness may vary depending on the nature of the sediment and speed of travel. At the sediment 4,8 facing the main surface 15 of the Rüttelbleche 9 steel flanges 6 are welded at different distances and dimensions along the pulling direction of the dredgers. The dimensions and the distances are chosen so that these flanges completely penetrate into the sediment on this, and the supernatant water can penetrate tangentially into the loosened sediment mainly on the side of the vibrating plate. The directed pressure of the protruding water body substantially supports the force of each on the

Rüttelblechen 9 attached eccentric, vibrator or other mechanical

Pulse generator 12. By these cyclic impulses, the pore water pressure is successively increased, the sediment volume increases, the grain-to-grain pressure, the shear strength and thus the internal friction decreases. A quasi-soil liquefaction is created, which substantially facilitates the erosion and rearrangement by the conventional methods. As a result, consolidated, hard as well as thixotropic sediments in the water-saturated zone are faster, larger, more environmentally friendly and easier to relocate using the water injection process or the hopper dredger.

In order to protect the macroorganisms from destruction or damage by pumping, the vibrating plates 9 are mounted so far before the too strong water suction and pressure that animals are baffled and can escape.

In order to protect flocks of small fish after the spawning period from the pump suction and thus from destruction, the dredging work in the relevant time can only be done with the vibrating plate 9, without use of hydropneumatic agents are performed. The currents in tidal waters and the respective water power counteract the sedimentation. For example, in rivers often partially fast-growing, small sediment banks, which hinder the navigation. The sedimentation at these points can be temporarily counteracted with the dredging method according to the invention alone (ie without suction dredger or WI device), so as to obtain the necessary navigation depth.

The invention can be used as needed in solid sandy to muddy soils. Characteristic of the sedimentary sediments are predominantly fine sand fractions, which have a straight grain distribution. Experience has shown that this

Constellation the pore spaces very strong, thereby the density is higher, the friction greater and the strength increases disproportionately. In addition to the fine sands, these sediments contain up to a third of clay components, which cause the thixotropic properties and behave in a similar manner to spring and damping elements. In this case, a higher pressure on the sediment surface is necessary, which is caused by the weight of the vibrating plate 9 and the outgoing from the ship strut 10. In softer sediments, where there is a risk that the vibrating plate 9 sinks due to its own weight, so that it can only be moved with great force, it is held by buoyant body 20 at the sediment surface. A deep penetration of the vibrating plates in soft sediment, can by buoyancy with z. B. variable inflatable, large ball fenders can be effected. Thus, with the method according to the invention with little energy input, all current sediments can be influenced in a way that makes them more fluid.

It is known that at the resonance frequency - even with sediments - with low energy a stronger deformation can be achieved. Therefore, in the inventive

Excavator method worked mostly with this optimal frequency. This can be determined in laboratory tests. The aim is to reduce the energy input when using the hydraulics. In pilot plant experiments is in the ratio of mechanical dynamic - to hydraulic energy input of 1: 700 KW / m ² a performance increase of the excavator performance of 100% has been determined.

In order to optimize the use of energy for the quasi-liquefaction of the sediment, the resonance of the sediments to be relocated is sought. After initial measurements, these are usually 9 to 20 Hz.

During shaking, the pore water in the sediment contributes to the depth of the sediment layer during the transmission of the fractions.

The stable corrugation formations of the sands (eg in the Elbe), which occur across the riverbed, form quickly and firmly and can severely hinder shipping. The

Sediment formations - crests to sediment valleys - may have a height difference of> 10 m and often have to be deepened quickly. The crests are often removed with the dredgers and transferred to the wells. With the

Excavator method according to the invention can be worked faster, more spacious and cheaper in these areas. This is especially beneficial in tidal currents, where working hours are severely limited.

In summary, in the excavator method according to the invention the hydrostatic pressure of the overlying body of water is tangentially around the vibrating plate in the loosened

Poured clean rooms to make the sediment flowable. The particularly low-energy relaxation of the sediment occurs through impulses in the resonance area of the sediments to be processed.

The pressure on the sediment is controllable, e.g. through the use of buoyancy bodies.

Claims

Patent claims 1. A method for removing sandy and / or silty deposits on soil surfaces of waters optionally by means of hydropneumatic process, in particular water inj ektion, suction dredging or the like, in which subjecting the sandy / silty deposit to be removed, optionally before the application of the hydro-pneumatic removal process, to a force reducing the viscosity of the deposit, characterized in that the pressure exerted by the force applying devices on the deposit is made variable , 2. The method of claim 1, wherein causing the force on the deposition surface by mechanical stress of the deposit, in particular by shaking and shearing stress. 3. The method of claim 1 or 2, wherein the force is applied in sufficiently short time interval, in particular immediately before the application of the hydropneumatic process. 4. The method according to any one of claims 1-3, wherein the sandy / silty deposit has thixotropic properties. 5. The method according to any one of claims 1-4, wherein the sandy / silty deposit also includes clays, in particular with platelet-shaped particles. 6. The method according to any one of claims 1-5, wherein the sandy / silty deposit has a substantially linear particle size distribution, in particular in the sand content. 7. The method according to any one of claims 1-6, wherein the deposit is treated according to the claim and then converted by means of a water injection method into a sufficiently flowable density layer. 8. The method according to any one of claims 1-6, wherein the deposit according to any one of claims 1-6 treated and then removed by means of a suction dredger method. 9. The method of claim 8, wherein the removed material from sucked water is at least partially separated and the separated water is returned (Suction Hopper Dredging). 10. The method according to any one of the preceding claims, wherein one waa the buoyancy of the device for adjusting the pressure. 1 1. A method according to any one of the preceding claims, wherein the Force generated by means of a vibration and / or vibration movement whose frequency is close to the resonant frequency of the deposit or equivalent. 12. The method of claim 11, wherein the frequency is in the range of 9 to 20 Hz. 13. Device for removal of sandy / schluffi ger deposits Bottoms of bodies of water, in particular according to any one of claims 1-12, having means for applying mechanical force to the surface of the deposit to be removed hydropneumatically, the pressure of which on the deposit being variable. 14. The apparatus of claim 13, wherein the means include vibrators, shaving heads, vibrators, eccentrics, and the like. 15. The apparatus of claim 13 or 14, which is designed as a watercraft, in particular as a ship, wherein the means for applying force to the Water bottom are lowered. 16. Device according to one of claims 13 - 15, further equipped with means for applying a hydropneumatic removal process. 17. Device according to one of the preceding claims, wherein the Mechanisms for mechanical force comprise a vibrating plate (9), which is preferably attached to the suction pipe (2) of a suction dredge (1) between the water Inj ektionsrohr (6) of a water-injection excavator (5). 18. The apparatus of claim 17, wherein the attachment of the vibrating plate (9) by means of struts (10) on the suction pipe (2) or on the injection pipe (6), wherein optionally provided devices for adjusting the pressure, the Vibrating plate (9) exerts on the sediment. 19. Device according to one of claims 17 and 18, wherein the vibrating plate (9) is connected to a vibrator. 20. Device according to one of claims 17 - 19, wherein the vibrating plate (9) with lamellae (16) is provided, which penetrate into the sediment during operation. 21. Device according to one of the preceding claims, wherein the vibrating plate (9) with means (20) is connected, which can be adjusted by means of buoyancy, the pressure of the vibrating plate (9) on the sediment (4, 8).