Vibro-replacement gravel grouting combined in-situ anti-seepage curing method suitable for loose accumulation body

Abstract

The invention provides a vibro-replacement gravel grouting and in-situ anti-seepage solidification combined method suitable for a loose accumulation body, belongs to the technical field of foundation reinforcement, and solves the problem of considering in-situ solidification and anti-seepage functions of the loose accumulation body and weakly cemented sand in a water-rich environment. The method specifically comprises the steps that a cushion layer is laid, and a construction site below the water surface is piled and filled to the water surface level; positioning the vibroflot; primary pore forming; cleaning the hole for the second time; graded broken stones are put into the holes, and a vibroflot is used for conducting horizontal vibration, so that the stones in the holes are vibrated to be dense; anti-seepage reinforcing grouting holes are evenly formed and drilled between the vibro-replacement gravel piles; a sticky rice-based cementing material is poured, specifically, the sticky rice-based cementing material with controllable condensation is poured into the grouting holes; and dynamic sounding quality evaluation: performing quality evaluation on the composite foundation by utilizing dynamic sounding equipment. On the premise of meeting the environmental protection of the natural resource heritage area restoration means, the seepage prevention of the calcareous sand stratum in the saturated water state is realized, the foundation reinforcement effect is enhanced, and the quality of the composite foundation is evaluated.

Description

Technical Field

[0001] The present invention relates to the field of anti-seepage solidification of loose deposits under special geological conditions, and in particular to a vibro-rock grouting combined with in-situ anti-seepage solidification method suitable for loose deposits. The invention aims at the loose travertine sand in a saturated state at the dam base layer, the bearing capacity of cemented travertine sand, and the loose deposits in the channel that are difficult to meet engineering requirements. At the same time, the restoration means of natural resource heritage sites must meet environmental protection, originality, authenticity, and pollution-free standards. Background Art

[0002] Under suitable environmental conditions, travertine is mostly formed in surface karst springs, rivers, lakes, etc. It is a special large-pore secondary calcium carbonate sediment. During the sedimentation process, porous sponge-like, thin-layer shell-like or block-like structures will be formed, which have complete structures and high strength under natural conditions. When travertine is subjected to external forces such as earthquakes, its original structure will be broken and particles will be crushed, resulting in a decrease in the stability of travertine, and finally forming loose travertine sand. The construction of water conservancy projects on such soils faces the problem that the bearing capacity of loose travertine sand and cemented travertine sand in the saturated state of the base layer is difficult to meet the requirements of the project for structural stability. Traditional foundation solidification methods include but are not limited to the following three: strong tamping method, chemical reinforcement method and vibration method. The above-mentioned foundation solidification methods have obvious limitations in water conservancy projects for the restoration of travertine sand natural resource heritage sites, and there are problems such as pollution of the natural ecological environment, long construction period, and poor solidification effect.

[0003] The vibro-compacted stone pile consolidation method has a history of more than 70 years and has been widely used in the field of in-situ dynamic foundation reinforcement, especially in the reinforcement scenarios of soft soil, sand, silt and other strata. According to a large number of engineering practices, the bearing capacity of the composite foundation can reach up to 300-400kPa when the pile-soil stress ratio and replacement rate are properly designed; thanks to the rapid development of vibrators, the hole-making and pile-making capabilities have also been significantly improved, with the maximum hole-making depth reaching more than ten meters, and it can overcome the problems of stuck holes and pile position deviation that may exist during construction. Although the research and application of vibro-compacted stone piles at home and abroad are relatively common, there are few examples of using the vibro-compacted stone pile consolidation method to consolidate special soil strata such as calcareous sand under saturated conditions. In addition, although the vibro-compacted stone pile method can be used to compact the soil between piles to improve the bearing capacity of the foundation. However, the pores between sand and gravel make the foundation have high permeability, which can easily induce penetration damage of the foundation soil under the action of water pressure, resulting in uneven settlement or water loss due to excessive permeability, thus failing to achieve the expected repair effect. In summary, the single vibro-stone pile solidification method is not ideal when solving the problem of calcareous sand, a special soil layer under saturated conditions. Therefore, a more effective and practical reinforcement process is urgently needed. Summary of the invention

[0004] The purpose of the present invention is to provide a vibro-compacted gravel grouting combined with in-situ anti-seepage solidification method suitable for loose accumulation bodies. On the basis of the vibro-compacted gravel pile solidification method, the anti-seepage grouting process of glutinous rice-based cementitious materials is combined. On the premise of meeting the environmental protection, original, authentic and pollution-free standards of natural resource heritage site restoration methods, the seepage resistance of calcareous sand strata in a saturated state is achieved, the foundation reinforcement effect is enhanced, and finally the quality assessment of the composite foundation is carried out based on the dynamic sounding test method.

[0005] To achieve the above object, the present invention provides a vibro-rock grouting combined with in-situ anti-seepage solidification method applicable to loose accumulation bodies, and performs quality assessment of composite foundation based on dynamic penetration testing, comprising the following steps:

[0006] Step 1: Paving the cushion layer, filling the construction site below the water surface to the water surface;

[0007] Step 2: Position the vibrator and calibrate the position of the vibrator;

[0008] Step 3: Initial hole making: start the vibrator, and after the vibrator operates normally, start drilling and making holes;

[0009] Step 4: Secondary hole cleaning: Use a vibrator to perform secondary cleaning on the filling hole;

[0010] Step 5: Vibrate the filler: put graded crushed stone into the hole and use a vibrator to vibrate horizontally to make the stone in the hole dense;

[0011] Step 6: Evenly arrange and drill grouting holes for anti-seepage reinforcement of glutinous rice-based cementitious materials between the vibro-compacted gravel piles;

[0012] Step seven: Fill the glutinous rice-based gelling material and pour the glutinous rice-based gelling material into the grouting hole.

[0013] Step 8: Dynamic probing quality assessment: Use dynamic probing equipment to conduct quality assessment of the composite foundation.

[0014] Preferably, in step one, limestone crushed stones are used for laying the cushion layer, and the crushed stones have a particle size range of 10 to 50 cm.

[0015] Preferably, in step 2, the tip of the vibrator is aligned with the pile position, the lower water spray port is opened, and the position of the vibrator is corrected by a water jet, with the deviation not exceeding 5 cm.

[0016] Preferably, in step 3, the clean water pump is first started to supply water, and the vibrator is started when the water pressure and water volume of the water outlet at the lower end of the vibrator reach the requirements. After the water flow, water pressure, current, voltage, air pressure and vibrator are running normally, the hole-making operation is started, and the hole-making current is 115A and the water pressure is 0.4-0.6Mpa.

[0017] Preferably, when filling in step 5, the bottom end of the vibrator is 30 to 50 cm away from the bottom of the hole, the graded crushed stone particle size is 4 to 15 cm, and the thickness of each filling is 50 cm. When the current of the submersible motor reaches the density current of 115A, it continues to be dense, and the vibration retention time is 20 to 25s, and the filling density process is completed. The density water pressure in this process is 0.4 to 0.6 MPa. During the filling process, the filling should be evenly and appropriately applied around the vibrating hole to avoid the deviation of the vibrator.

[0018] Preferably, the grouting holes in step six are arranged in a plum blossom shape.

[0019] Preferably, during grouting in step seven, the glutinous rice-based slurry can be pumped for 10 to 20 minutes, and a bottom-up segmented grouting with in-hole isolation is adopted. The grouting end standard is preferentially controlled by the grouting volume. When the design pressure of 0.8 to 1.0 MPa is reached, the injection is continued for 5 minutes.

[0020] Preferably, in step eight, the dynamic probing adopts an ultra-heavy drop hammer.

[0021] Therefore, the present invention adopts the above-mentioned vibro-stone grouting combined with in-situ anti-seepage solidification method applicable to loose accumulation bodies, which has the following advantages:

[0022] The construction materials are pollution-free: the present invention will not produce any water-polluting substances during the construction process, and will not have any impact on the water quality and the ecological environment, thus meeting the requirements of environmental protection, originality, authenticity, and pollution-free standards for the restoration of natural resource heritage sites.

[0023] Good solidification effect: the present invention can make up for the problem that a single vibro-stone pile solidification method can solve the problem that the special soil layer of calcareous sand under saturated water conditions induces penetration damage of foundation soil due to water pressure, thereby causing uneven settlement or water loss due to excessive permeability.

[0024] High curing efficiency: Compared with other traditional reinforcement methods, the present invention has a simple construction process and can greatly shorten the construction period.

[0025] Good economic benefits: the materials used in the construction process of the present invention can be obtained locally, realizing resource recycling, and thus having good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The technical solution proposed by the present invention is described in more detail below through drawings and examples.

[0027] Figure 1 It is a flow chart of the overall solution of the present invention;

[0028] Figure 2 This is a schematic diagram of the construction cross-section test of the present invention;

[0029] Figure 3 It is a schematic diagram of the construction plane of the present invention;

[0030] Figure 4 To invent pile test results Figure 1 ;

[0031] Figure 5 To invent the pile-to-pile diagram test results Figure 2 ;

[0032] Reference numerals

[0033] 1. Vibratory crushed stone pile hole; 2. Anti-seepage reinforcement grouting hole; 3. Glutinous rice-based cementitious material; 4. Graded crushed stone; 5. Vibrator. DETAILED DESCRIPTION

[0034] The technical contents of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0035] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The words "include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but do not exclude other elements or objects. The words "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] Example

[0037] See also Figure 1 The present invention provides a vibro-stone grouting combined with in-situ anti-seepage solidification method applicable to loose accumulation bodies, comprising the following steps:

[0038] Step 1: Paving the cushion layer: Use limestone crushed stones to fill the construction site below the water surface. The crushed stones have a particle size range of 10 to 50 cm and are filled to the water surface.

[0039] Step 2: Figure 2 , use a crane to lift the vibrator 5 to the top of the vibratory crushed stone pile hole 1, align the lower tip of the vibrator 5 with the vibratory crushed stone pile hole 1, and after the vibrator 5 stops shaking, open the water spray port under the vibrator 5, and fine-tune the vibrator 5 through the water jet to ensure that the error is within 5 cm, thereby completing the precise positioning of the vibrator 5.

[0040] Step 3: Start the vibrator 5, check the water pressure and voltage of the clean water pump, and check whether the vibrator can operate normally. After the water flow, water pressure, current, voltage, and air pressure of the vibrator 5 are operating normally, the drilling can be carried out. The drilling current is 115A and the water pressure is 0.4-0.6Mpa. The vibrator 5 is hoisted by a crane and slowly dropped. The vibration of the vibrator and the impact of high-pressure water penetrate the vibrator 5 into the formation. When the vibrator 5 is lowered to the designed depth of 1000cm of the vibratory gravel pile hole 1, the initial drilling operation is completed.

[0041] Step 4: In order to prevent residual materials in the vibro-stone pile hole 1 from affecting the construction, the vibro-stone pile hole 1 needs to be cleaned a second time according to step 3.

[0042] Step 5. After the two drilling operations are completed, lift the vibrator 5 to ensure that the lower part of the vibrator 5 is 30 to 50 cm away from the bottom of the hole, fill in graded gravel 4 with a gradation of 4 to 15 cm, and fill in layers with a filling thickness of 50 cm each time. Then turn on the vibrator 5 for horizontal vibration. When the current of the submersible motor reaches the density current of 115A, the vibration retention time reaches 20 to 25s, and the density water pressure reaches 0.4 to 0.6Mpa, the filling density operation is completed. Press the attached Figure 3 The other vibrating gravel pile holes 1 are drilled. During this process, the vibrating holes should be filled evenly and appropriately around the holes to avoid the vibrator from shifting.

[0043] Step 6: Follow steps 3 and 4 to press the attachment between the vibrating gravel pile holes 1. Figure 3 , evenly arrange 2 cementitious material grouting holes and complete the construction.

[0044] Step seven, filling the glutinous rice-based gelling material 3, pouring the glutinous rice-based gelling material 3 into the gelling material grouting hole 2 to prevent the foundation soil from being damaged by water pressure and causing uneven settlement and water loss due to excessive permeability.

[0045] Step 8: Use ultra-heavy gravity penetration equipment to evaluate the quality of the composite foundation formed in the above steps. During the evaluation process, the specified drop distance and operation method should be followed. The maximum inclination error of the probe rod should not exceed 2%, and every time the probe rod is driven into the formation 1m, the probe rod should be rotated to reduce the energy loss caused by friction between the probe rod and the foundation soil, so as to ensure the accuracy and effectiveness of the detection results. The test results are as follows: Figure 4 and Figure 5 .

[0046] Therefore, the present invention adopts the above-mentioned vibro-stone grouting combined with in-situ anti-seepage solidification method suitable for loose accumulation bodies, and the construction materials are pollution-free: the present invention will not produce water-polluting substances during the construction process, and has no impact on the water quality and the ecological environment, meeting the environmental protection, original, authentic and pollution-free standards for the restoration of natural resource heritage sites. Good solidification effect: the present invention can make up for the single vibro-stone pile solidification method in solving the problem of infiltration damage to the foundation soil induced by water pressure in the special soil layer of calcareous sand under saturated conditions, thereby causing uneven settlement or water loss due to excessive permeability. High solidification efficiency: compared with other traditional reinforcement methods, the present invention has a simple construction process and can greatly shorten the construction period. Good economic benefits: the materials used in the construction process of the present invention can be sourced locally, realizing resource recycling, and therefore has good economic benefits.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A vibro-grouting combined with in-situ anti-seepage solidification method for loose accumulation bodies, characterized in that: The following steps are involved: Step 1: Pad laying, fill the construction site below the water surface to the water surface; Step 2: Position the vibrator and calibrate the position of the vibrator; Step 3: Initial hole making: start the vibrator, and after the vibrator operates normally, start drilling and making holes; Step 4: Secondary hole cleaning: Use a vibrator to perform secondary cleaning on the filling hole; Step 5: Vibration filling: put graded crushed stone into the hole and use a vibrator to vibrate horizontally to make the stone in the hole dense; Step 6: Evenly arrange and drill grouting holes for anti-seepage reinforcement of glutinous rice-based cementitious materials between the vibro-compacted gravel piles; Step 7, filling the glutinous rice-based gelling material, pouring the glutinous rice-based gelling material into the grouting hole; Step 8: Dynamic probing quality assessment: Use dynamic probing equipment to conduct quality assessment of the composite foundation.

2. The vibro-stone grouting combined with in-situ anti-seepage solidification method for loose accumulation bodies according to claim 1, characterized in that: In step 1, the cushion layer is paved with limestone gravel, the gravel particle size range is 10 to 50 cm, and the paving height is 10 cm above the water surface.

3. The vibro-grouting combined in-situ anti-seepage solidification method for loose accumulation bodies according to claim 1, characterized in that: In step 2, the tip of the vibrator is aligned with the pile position, the lower water spray port is opened, and the position of the vibrator is corrected by the water jet, with the deviation not exceeding 5 cm.

4. The vibro-stone grouting combined with in-situ anti-seepage solidification method for loose accumulation bodies according to claim 1, characterized in that: In step three, first start the clean water pump to supply water. When the water pressure and water volume of the water outlet at the lower end of the vibrator reach the requirements, start the vibrator. After the water flow, water pressure, current, voltage, air pressure and vibrator are operating normally, start the hole-making operation. The hole-making current is 115A and the water pressure is 0.4-0.6MPa.

5. The vibro-stone grouting combined in-situ anti-seepage solidification method applicable to loose accumulation bodies according to claim 1, characterized in that: When filling in step five, the bottom end of the vibrator is 30 to 50 cm away from the bottom of the hole, the particle size of the graded gravel filled in is 4 to 15 cm, and the thickness of each filling is 50 cm; when the current of the submersible motor reaches the density current of 115A, it continues to be dense, and the vibration retention time reaches 20 to 25s, and the filling density process is completed; the density water pressure in this process is 0.6Mpa, and the filling process should be evenly and appropriately filled around the vibrating hole to avoid the deviation of the vibrator.

6. The vibro-stone grouting combined in-situ anti-seepage solidification method applicable to loose accumulation bodies according to claim 1, characterized in that: In step six, the grouting holes are arranged in a plum blossom shape, and the hole depth exceeds the length of the vibratory pile by 1m.

7. The vibro-stone grouting combined with in-situ anti-seepage solidification method for loose accumulation bodies according to claim 1, characterized in that: The grouting material in step seven is a glutinous rice-based slurry with controllable coagulation and a pumpable period of 15 minutes. The grouting adopts bottom-up segmented grouting with in-hole isolation. The grouting end standard is preferentially controlled by the grouting volume. When the design pressure of 1.0 MPa is reached, the injection is continued for 5 minutes.

8. The vibro-stone grouting combined with in-situ anti-seepage solidification method applicable to loose accumulation bodies according to claim 1, characterized in that: In step eight, the dynamic probing uses an ultra-heavy drop hammer.

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