Construction device and method for water-impact bored pile encountering karst cave

Abstract

The application discloses a construction device and method for water-impact drilling bored pile encountering karst cave, and belongs to the technical field of bored pile construction technology. The construction device comprises an operation platform, an outer protection cylinder is arranged below the tabletop of the operation platform, an inner protection cylinder is arranged in the outer protection cylinder, slurry outlets are arranged on the surface of the cylinder body of the inner protection cylinder at intervals, rolling needle bearings are arranged on the inner wall of the outer protection cylinder at intervals, and the outer protection cylinder and the inner protection cylinder slide relative to each other. The application is simple in operation and easy to implement. The mud flows from the outer protection cylinder to the inner protection cylinder, is circulated and discharged from the inner protection cylinder, and forms mud recirculation. The mixed soil is composed of cement, clay, coarse sand and gravel, so that the sealing of the karst cave is good. Through the sealing of the karst cave, mud recirculation and the whole-process following of the inner protection cylinder, the material consumption is saved, the efficiency is improved, and the hole forming quality is ensured.

Description

Technical Field

[0001] This invention relates to the field of impact drilling and grouting pile construction technology, and more specifically, to a construction device and method for underwater impact drilling and grouting piles encountering karst caves. Background Technology

[0002] Currently, most cast-in-place piles are constructed using rotary drilling and percussion drilling, with the choice depending on the geological conditions and rock hardness. Rotary drilling piles are mostly used in geology where the rock is not too hard, while percussion drilling piles are mostly used in geology where the rock is harder. Percussion drilling involves using a heavy hammer to break up the rock, and then circulating mud to carry the broken rock out. Combined with the installation of a casing, a mud wall is formed, ultimately forming the hole. In some areas of my country, when constructing percussion drilling piles underwater, due to special geological conditions such as fissures or karst caves, mud loss occurs, making mud circulation impossible. Therefore, in most cases, crushed stone or clay is filled inside the casing and repeatedly driven to complete the hole. However, this method involves a large workload, hole collapse, and pile diameter enlargement, which also seriously affects the construction period and is inefficient. Therefore, the existing underwater percussion drilling construction method for karst caves has certain limitations. Summary of the Invention

[0003] 1. The technical problem that the invention aims to solve

[0004] To address the shortcomings and deficiencies of existing technologies, this invention provides a construction device and method for underwater impact drilling and grouting piles encountering karst caves. This invention is simple to operate and easy to implement. The drilling mud flows from the outer casing to the inner casing and is then circulated out from the inner casing, forming a mud recirculation. The mixed soil, composed of cement, clay, coarse sand, and gravel, effectively seals the karst cave. Through karst cave sealing, mud recirculation, and continuous inner casing operation, material consumption is saved, efficiency is improved, and the quality of the borehole is guaranteed.

[0005] 2. Technical Solution

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] The present invention provides a construction device for underwater impact drilling and grouting piles encountering karst caves, comprising an operating platform, an outer casing provided under the platform surface, an inner casing provided inside the outer casing, and grout outlets spaced apart on the surface of the inner casing.

[0008] Furthermore, the inner wall of the outer casing is provided with needle roller bearings at intervals, and the outer casing and the inner casing slide relative to each other.

[0009] Furthermore, the operating platform is erected on the upper part of the water layer, and a clay layer and a rock layer are arranged in sequence at the bottom of the water layer.

[0010] Furthermore, the inner diameter of the inner casing is the same as the pile diameter.

[0011] Furthermore, the clay layer is a silty and muddy clay layer.

[0012] A method for constructing underwater impact drilled cast-in-place piles encountering karst caves, comprising the following steps:

[0013] Step 1: Locate the defense line. After determining the pile position, use a heavy hammer to drive the outer casing through the water layer and clay layer to the top of the rock layer, and then connect and fix the outer casing to the operating platform.

[0014] Step 2: The impact drill hammer is used for construction inside the outer casing, and the mud generated during the construction process is circulated.

[0015] Step 3: After encountering a cave inside the rock layer, the mud begins to descend. Determine the size of the cave based on the rate of descent.

[0016] Step 4: After determining the proportion and amount of mixed soil according to the size of the karst cave, fill the mixed soil inside the outer casing until it is 1 meter higher than the grout leakage surface;

[0017] Step 5: Install the inner casing inside the outer casing using a needle roller bearing. After adding diluted mud into the gap between the outer and inner casings, continue drilling with the impact drill hammer. A slurry outlet is set on the inner casing.

[0018] Step Six: The thick mud inside the inner casing is pumped to the outer slurry tank. The diluted mud flows into the inner casing through the slurry outlet at the gap between the outer and inner casings, forming a mud circulation.

[0019] Step 7: The inner casing is advanced simultaneously with the depth of the hole;

[0020] Step 8: After construction reaches the designed elevation of the pile bottom, clean the hole, pull out the outer casing, and fix the inner casing to the operating platform to complete the hole formation.

[0021] Furthermore, the mixed soil is composed of cement, clay, coarse sand, and crushed stone.

[0022] Furthermore, the mud includes thick mud and diluted mud. In step two, the mud produced during construction is thick mud, and in step six, the mud added to the gap between the outer casing and the inner casing is diluted mud.

[0023] Furthermore, the diluted mud filling the gap between the outer and inner casings has a higher liquid level than the thick mud inside the inner casing.

[0024] 3. Beneficial effects

[0025] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0026] This invention is simple to operate and easy to implement. The mud flows from the outer casing to the inner casing and is then circulated out from the inner casing, forming a mud recirculation. The mixed soil is composed of cement, clay, coarse sand, and gravel, which ensures good sealing of the karst cave. Through karst cave sealing, mud recirculation, and the continuous follow-up of the inner casing, material consumption is saved, efficiency is improved, and the quality of hole formation is guaranteed. Attached Figure Description

[0027] Figure 1 This is a top view of the present invention;

[0028] Figure 2 This is a schematic diagram of the construction of the outer casing of the present invention;

[0029] Figure 3 This is a schematic diagram of the invention encountering a cave;

[0030] Figure 4 This is a schematic diagram of the filling construction of karst caves according to the present invention;

[0031] Figure 5 This is a schematic diagram of the construction of the protective casing inside the karst cave according to the present invention;

[0032] Figure 6 This is a schematic diagram of the construction to the pile bottom elevation after encountering a karst cave according to the present invention;

[0033] Figure 7 This is a schematic diagram of the completed hole formation process when encountering a karst cave, according to the present invention.

[0034] In the diagram: 1. Water layer; 2. Outer casing; 3. Inner casing; 4. Operating platform; 5. Clay layer; 6. Rock layer; 7. Cave; 8. Mud; 801. Thick mud; 802. Diluted mud; 9. Mixed soil; 10. Needle roller bearing; 11. Slurry outlet. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0036] Example 1

[0037] from Figure 1 As can be seen, a construction device for underwater impact drilling and grouting piles encountering karst caves in this embodiment includes an operating platform 4, an outer casing 2 is provided under the platform of the operating platform 4, an inner casing 3 is provided inside the outer casing 2, and grout outlets 11 are spaced apart on the surface of the inner casing 3.

[0038] The inner wall of the outer casing 2 is provided with needle roller bearings 10 at intervals. The outer casing 2 and the inner casing 3 slide relative to each other to ensure the verticality of the inner casing 3 and provide conditions for impact drilling. The inner diameter of the inner casing 3 is the same as the pile diameter.

[0039] The operating platform 4 is erected on the upper part of the water layer 1, and the bottom of the water layer 1 is successively set with a clay layer 5 and a rock layer 6.

[0040] Clay layer 5 is a layer of silty clay and muddy clay.

[0041] A method for constructing underwater impact drilled cast-in-place piles encountering karst caves, comprising the following steps:

[0042] Step 1: Locate the defense line. After determining the pile position, use a heavy hammer to push the outer casing 2 through the water layer 1 and the clay layer 5 to the top of the rock layer 6, and then connect and fix the outer casing 2 to the operating platform 4.

[0043] Step 2: The impact drill hammer is used for construction inside the outer casing 2, and the mud 8 generated during the construction process is circulated.

[0044] Step 3: After encountering the cave 7 inside the rock layer 6, the mud 8 begins to descend. Determine the size of the cave 7 based on the descent speed.

[0045] Step 4: Based on the size of the karst cave 7, determine the proportion and amount of mixed soil 9, and then fill the outer casing 2 with mixed soil 9 until it is 1 meter higher than the grout leakage surface.

[0046] Step 5: Install the inner casing 3 inside the outer casing 2 through the needle roller bearing 10. After adding diluted mud 8 into the gap between the outer casing 2 and the inner casing 3, continue the operation with the impact drill hammer. Add thin mud 8 into the outer casing 2 and the inner casing 3, with the height higher than the thick mud 8 inside the inner casing 3. Set the slurry outlet 11 on the inner casing 3.

[0047] Step 6: The thick mud slurry 8 inside the inner casing 3 is pumped to the outer slurry tank. The diluted mud slurry 8 flows from the gap between the outer casing 2 and the inner casing 3 through the slurry outlet 11 into the inner casing 3, forming a mud slurry circulation.

[0048] Step 7: The inner casing 3 is advanced simultaneously with the depth of the hole;

[0049] Step 8: After construction reaches the designed elevation of the pile bottom, clean the hole, pull out the outer casing 2, and fix the inner casing 3 to the operating platform 4 to complete the hole formation.

[0050] Mixed soil 9 is composed of cement, clay, coarse sand and gravel.

[0051] The mud slurry 8 includes thick mud slurry 801 and diluted mud slurry 802. In step two, the mud slurry 8 generated during construction is thick mud slurry 801. In step six, the mud slurry 8 added to the gap between the outer casing 2 and the inner casing 3 is diluted mud slurry 802.

[0052] The diluted mud 802 added to the gap between the outer casing 2 and the inner casing 3 has a higher liquid level than the thick mud 801 inside the inner casing 3.

[0053] The mud slurry 8 flows from the outer casing 2 through the slurry outlet 11 into the inner casing 3, and then is discharged from the inner casing 3 to the outer slurry pool, which effectively improves the circulation of the mud slurry 8 and the cleaning of slag. The mixed soil 9 is composed of cement, clay, coarse sand and gravel. The specific proportion is determined according to the size of the karst cave and the rate of slurry leakage. The inner casing 3 is advanced at the same time as the progress to ensure that the casing passes smoothly through the karst cave 7 and completes the drilling.

[0054] This invention combines an operating platform 4, an outer casing 2, an inner casing 3, mud 8, and mixed soil 9, and implements the process in a water layer 1, a clay layer 5, and a rock layer 6. By treating the karst cave 7, the hole for the cast-in-place pile is completed, forming a construction method for underwater percussion drilling cast-in-place piles encountering karst caves. This method aims to solve the problems of quality, efficiency, and cost associated with conventional treatment methods for karst cave construction in underwater percussion drilling cast-in-place piles.

[0055] This invention is simple to operate and easy to implement. The mud slurry 8 flows from the outer casing 2 to the inner casing 3 and is discharged from the inner casing 3 in a circular manner, forming a mud slurry recirculation. The mixed soil 9 is composed of cement, clay, coarse sand and gravel, which makes the karst cave well sealed. Through the karst cave sealing, mud slurry recirculation and the continuous follow-up of the inner casing, the amount of materials used is saved, the efficiency is improved and the hole formation quality is guaranteed.

[0056] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A construction method for a construction device used in underwater impact drilling and grouting piles encountering karst caves, the construction device comprising an operating platform (4), characterized in that: The operating platform (4) is provided with an outer protective cylinder (2) under the table surface and an inner protective cylinder (3) inside the outer protective cylinder (2). The inner protective cylinder (3) has slurry outlets (11) spaced apart on its surface. The inner wall of the outer casing (2) is provided with needle roller bearings (10) at intervals, and the outer casing (2) and the inner casing (3) slide relative to each other; The operating platform (4) is erected on the upper part of the water layer (1), and the bottom of the water layer (1) is provided with a clay layer (5) and a rock layer (6) in sequence. The construction method and steps are as follows: Step 1: Positioning and setting out. After determining the pile position, use a heavy hammer to push the outer casing (2) through the water layer (1) and clay layer (5) to the top of the rock layer (6), and connect and fix the outer casing (2) to the operating platform (4); Step 2: The impact drill hammer is used for construction inside the outer casing (2), and the mud (8) generated during the construction process is circulated; Step 3: After encountering the cave (7) inside the rock layer (6), the mud (8) begins to descend. The size of the cave (7) is determined based on the descending speed. Step 4: Based on the size of the karst cave (7), determine the proportion and amount of mixed soil (9), and fill the outer casing (2) with mixed soil (9) until it is 1 meter higher than the grout leakage surface; Step 5: Install the inner casing (3) inside the outer casing (2) through the needle roller bearing (10). After adding diluted mud (8) into the gap between the outer casing (2) and the inner casing (3), the impact drill hammer continues to operate. A slurry outlet (11) is set on the inner casing (3). Step 6: The thick mud (8) inside the inner casing (3) is pumped to the outer slurry pool. The diluted mud (8) flows from the gap between the outer casing (2) and the inner casing (3) through the slurry outlet (11) into the inner casing (3), forming a mud circulation. Step 7: The inner casing (3) is advanced simultaneously with the depth of the hole; Step 8: After construction reaches the designed elevation of the pile bottom, clean the hole, pull out the outer casing (2), fix the inner casing (3) to the operating platform (4), and complete the hole formation.

2. The construction method of the construction device for underwater impact drilling and grouting piles encountering karst caves according to claim 1, characterized in that: The inner diameter of the inner casing (3) is the same as the pile diameter.

3. The construction method of the construction device for underwater impact drilling and grouting piles encountering karst caves according to claim 1, characterized in that: The clay layer (5) is a silty and silty clay layer.

4. The construction method of the construction device for underwater impact drilling and grouting piles encountering karst caves according to claim 1, characterized in that: The mixed soil (9) is composed of cement, clay, coarse sand and gravel.

5. The construction method of the construction device for underwater impact drilling and grouting piles encountering karst caves according to claim 1, characterized in that: The mud (8) includes thick mud (801) and diluted mud (802). In step two, the mud (8) generated during construction is thick mud (801). In step six, the mud (8) added to the gap between the outer casing (2) and the inner casing (3) is diluted mud (802).

6. The construction method of the construction device for underwater impact drilling and grouting piles encountering karst caves according to claim 5, characterized in that: The diluted mud (802) added to the gap between the outer casing (2) and the inner casing (3) has a higher liquid level than the thick mud (801) inside the inner casing (3).

Images