Strong anti-permeability construction method of sandwich type membrane bag cofferdam suitable for sandy soil area

Abstract

The invention discloses a high-impermeability construction method of a sandwich type film bag cofferdam suitable for a sandy soil area, which specifically comprises the following steps of: positioning and cleaning a line, paving and filling woven bags of a main cofferdam, paving and filling back sand, paving and filling filling bags of an auxiliary cofferdam, paving and filling a leaking stoppage layer and paving coping woven bags in sequence. And when the multiple layers of main cofferdam woven bags and the multiple layers of auxiliary cofferdam filling bags are laid and filled, the purpose that the main cofferdam woven bags or the auxiliary cofferdam filling bags are completely attached to sand at the bottom of a riverbed or attached to the next layer of main cofferdam woven bags or the next layer of auxiliary cofferdam filling bags is achieved through positioning cones. While the overall stability of the film bag cofferdam is guaranteed, the problems that the first-layer film bag of a conventional film bag cofferdam is difficult to fix, and the connection tightness degree of interlayer film bags is poor are solved, and the anti-permeability performance of the film bag cofferdam is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy and water affairs engineering construction, in particular to a strong anti-seepage construction method of a sandwich membrane bag cofferdam suitable for sandy soil areas. Background Art

[0002] Membrane bag cofferdams are common water retaining structures in water conservancy projects. They are made of geotextile bags filled with sand and other permeable materials. They have good tensile and wear resistance and are simple, fast and economical in actual construction and production. Since the bottom membrane bag is fixed underwater, and considering the hydrostatic pressure, river water flow, flow rate and other indicators, the fixation of the bottom membrane bag and the anti-seepage performance of the final product face great challenges. The existing membrane bag cofferdams need to improve the degree of fit between the first layer of membrane bags and the base, the flatness of the interlayer membrane bags and the tightness of the connection, resulting in the weak anti-seepage performance of the membrane bag cofferdam. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a strong anti-seepage construction method for a sandwich membrane bag cofferdam suitable for sandy soil areas. While ensuring the overall stability of the membrane bag cofferdam, it solves the problems of the difficulty in fixing the first layer of membrane bags and the poor connection tightness of the interlayer membrane bags of conventional membrane bag cofferdams, thereby greatly improving the anti-seepage performance of the membrane bag cofferdam.

[0004] The technical solution of the present invention is:

[0005] The strong anti-permeability construction method of the sandwich membrane bag cofferdam suitable for sandy soil areas specifically includes the following steps:

[0006] (1) Laying out, positioning and cleaning: Position the laying bottom edge of the main cofferdam filling bag and the auxiliary cofferdam filling bag of the sandwich film bag cofferdam, and clean the laying area;

[0007] (2) Paving and filling of the main cofferdam woven bags: The main cofferdam woven bags include multiple layers, and the width gradually decreases from bottom to top. Each layer of the main cofferdam woven bags is connected to a sand conveying pipe, and loose sand is filled into each layer of the main cofferdam woven bags through the sand conveying pipe. After each layer of the main cofferdam woven bags is filled and consolidated, the main cofferdam woven bags of the previous layer are continued to be filled. An underwater camera and a GPS positioning module are installed at the four corners of each layer of the main cofferdam woven bags. A traction rope is connected to the four corners of each layer of the main cofferdam woven bags. The underwater camera and the GPS positioning module are connected to the remote monitor through wireless communication. The underwater camera is used to monitor the moving image of the main cofferdam woven bags, and the GPS positioning module is used to collect the coordinate information of the four corners of the main cofferdam woven bags. When the remote monitor detects that the four corners of the main cofferdam woven bags deviate from the set point coordinates, the position of the main cofferdam woven bags is adjusted through the traction rope;

[0008] (3) Backing sand filling: When all the multi-layer main cofferdam woven bags are filled, backing sand is filled on the water-facing surface of the main cofferdam woven bags. The safety slope ratio of the backing sand on the water-facing surface after filling is 1:8-12;

[0009] (4) Paving of the secondary cofferdam filling bags: After the backing sand is paved, multi-layer secondary cofferdam filling bags are laid on the outer side of the backwater surface of the multi-layer main cofferdam woven bags. The width of the multi-layer secondary cofferdam filling bags is equal. The multi-layer secondary cofferdam filling bags are arranged obliquely from bottom to top. The axial direction of the inclination of the multi-layer secondary cofferdam filling bags is consistent with the axial direction of the inclination of the backwater surface of the multi-layer main cofferdam woven bags;

[0010] (5) Paving and filling of the plugging layer: After the multi-layer auxiliary cofferdam filling bags are filled, a layer of waterproof geotextile is laid at the bottom of the area between the multi-layer main cofferdam woven bags and the multi-layer auxiliary cofferdam filling bags, and the plugging layer is laid on the waterproof geotextile. The height of the backing sand, the multi-layer main cofferdam woven bags, the multi-layer auxiliary cofferdam filling bags and the top of the plugging layer is consistent;

[0011] (6) Laying of top-pressing woven bags: After the plugging layer is paved, a top-pressing woven bag is laid on the top surface of the plugging layer, and the two ends of the top-pressing woven bag in the width direction are respectively placed on the top of the multi-layer main cofferdam woven bag and the top of the multi-layer auxiliary cofferdam filling bag, thereby forming a sandwich film bag cofferdam consisting of the main cofferdam woven bag, backing sand, auxiliary cofferdam filling bag, plugging layer and top-pressing woven bag;

[0012] When the multi-layer main cofferdam woven bags and the multi-layer auxiliary cofferdam filling bags are laid, a positioning cone is pasted on the bottom surface of each layer of the main cofferdam woven bags or each layer of the auxiliary cofferdam filling bags near the four corners, and a patch type stress sensor is arranged on the outer wall of the positioning cone. The patch type stress sensor is connected to the remote monitor through wireless communication. When each layer of the main cofferdam woven bags or each layer of the auxiliary cofferdam filling bags is filled with loose sand, the positions of the four corners of the main cofferdam woven bags or the auxiliary cofferdam filling bags will expand and expand, and the positioning cone will be inserted into the sand at the bottom of the riverbed, or the main cofferdam woven bags or auxiliary cofferdam filling bags of the next layer When the collection surface of the patch stress sensor is completely in contact with the sand at the bottom of the riverbed, or with the loose sand in the next layer of main cofferdam woven bags or auxiliary cofferdam filling bags, the positioning cone is completely inserted into the sand at the bottom of the riverbed, or the loose sand in the next layer of main cofferdam woven bags or auxiliary cofferdam filling bags. At this time, the main cofferdam woven bags or auxiliary cofferdam filling bags are completely in contact with the sand at the bottom of the riverbed, or with the next layer of main cofferdam woven bags or auxiliary cofferdam filling bags, that is, the filling of loose sand is stopped, and the close fit of multiple layers of main cofferdam woven bags or multiple layers of auxiliary cofferdam filling bags is achieved, so as to achieve the purpose of strong anti-seepage.

[0013] The positioning cone is a hollow structure with an opening at the top. A spring vibrator and a pressure sensor are arranged inside the positioning cone. The pressure sensor is fixed at the tip of the positioning cone. The bottom end of the spring vibrator is connected to the pressure sensor. The top end of the spring vibrator extends from the top end of the positioning cone and is fixedly connected to the bottom surface of the main cofferdam woven bag. The pressure sensor is connected to the remote monitor through wireless communication. When each layer of the main cofferdam woven bag or each layer of the auxiliary cofferdam filling bag is filled with loose sand, the four corners of the main cofferdam woven bag or the auxiliary cofferdam filling bag will swell and expand, and when the positioning cone is inserted into the sand at the bottom of the riverbed, or into the main cofferdam woven bag or the auxiliary cofferdam filling bag of the next layer, the four corners of the main cofferdam woven bag or the auxiliary cofferdam filling bag will squeeze the top end of the spring vibrator, and the top end of the spring vibrator will squeeze into the interior of the positioning cone. At this time, the pressure sensor senses the pressure signal and transmits it to the remote monitor, and the remote monitor displays a signal that the positioning cone has been inserted.

[0014] The upper part of the positioning cone is a cylindrical structure, and the lower part is an inverted cone structure. The patch-type stress sensor is completely covered on the outer wall of the upper part of the positioning cone.

[0015] The sand conveying pipe is connected to the mud boat, the bottom of the mud boat is connected to the mud pump, the mud boat pumps water upward to flush the sand through the mud pump connected below, and then uses the sand conveying pipe to fill the sand into the main cofferdam woven bag or the auxiliary cofferdam filling bag. The inlet end of the sand conveying pipe connected to the mud boat and the outlet end connected to the main cofferdam woven bag or the auxiliary cofferdam filling bag are both provided with a sand content monitoring device, which includes a drainage pipe with a top connected to the sand conveying pipe, a switch valve arranged at the top of the drainage pipe, a loose sand filtering screen arranged at the bottom of the drainage pipe, and a measuring cylinder. Insert the part into the measuring cylinder. The measuring cylinder is marked with a set scale line. The horizontal height of the set scale line is higher than the horizontal height of the bottom of the drainage tube. When monitoring the sand content, open the switch valve, the sand water in the sand conveying pipe enters the drainage tube, the larger loose sand particles are intercepted by the loose sand filter screen, and the water flows into the measuring cylinder. When the water flow reaches the set scale line of the measuring cylinder, close the switch valve, and then separate the measuring cylinder from the drainage tube. At this time, the water capacity in the measuring cylinder is recorded as M, and the sand water capacity corresponding to the set scale line is N. The volume of loose sand in the sand water is NM, and the sand content When the sand content monitoring device detects that the sand content is lower than the set sand content, the mud boat and the mud pump are moved to other locations with high sand content for sand flushing.

[0016] A plurality of filling ports are evenly arranged on the top surface of the main cofferdam woven bag or the auxiliary cofferdam filling bag, and the plurality of filling ports are connected with corresponding filling hoppers and sand conveying pipes. The lower part of the filling hopper is inserted into the main cofferdam woven bag or the auxiliary cofferdam filling bag through the filling port, and the outlet end of the sand conveying pipe is inserted into the filling hopper. The sand conveying pipe conveys the loose sand in the sand water into the main cofferdam woven bag or the auxiliary cofferdam filling bag for sedimentation. When the loose sand is filled to the top of the main cofferdam woven bag or the auxiliary cofferdam filling bag, the water flows through the filling hopper and overflows.

[0017] Before laying each layer of the main cofferdam woven bags, a row of fixed piles are driven in the filling area along both sides of the embankment core at a distance of 3-5m from the main cofferdam woven bags, and the head, middle and tail of the main cofferdam woven bags along the length direction are fixed to the row of fixed piles with nylon ropes.

[0018] The top surface and bottom surface of each layer of main cofferdam woven bags or auxiliary cofferdam filling bags are sewn with geotextile belts.

[0019] Advantages of the present invention:

[0020] (1) The sandwich-type membrane bag cofferdam of the present invention is composed of a main cofferdam woven bag, backing sand, a secondary cofferdam filling bag, a leak-proof layer and a top pressure woven bag. The main cofferdam woven bag, backing sand, secondary cofferdam filling bag and leak-proof layer form a four-layer sandwich structure, which greatly improves the impermeability of the membrane bag cofferdam and ensures safe and reliable construction inside the cofferdam.

[0021] (2) The present invention is provided with a positioning cone, which can ensure that the multi-layer main cofferdam woven bags and the multi-layer auxiliary cofferdam filling bags, the first-layer main cofferdam woven bags or the auxiliary cofferdam filling bags are completely fitted with the base (sand and soil at the bottom of the riverbed), and the anti-seepage performance of the membrane bag cofferdam is greatly improved; and the ground construction personnel can grasp the positioning connection status of the positioning cone through the patch stress sensor, control the filling amount of loose sand, ensure the flatness of the membrane bag after filling with loose sand, improve the flatness of the interlayer membrane bag, and through the setting of the spring oscillator and the pressure sensor, it is convenient for the ground construction personnel to display the signal that the positioning cone has been inserted through the remote monitor, and timely check the positioning status and make position adjustments in time.

[0022] (3) In the present invention, the loose sand in the woven bags of the main cofferdam and the filling bags of the auxiliary cofferdam is filled by a mud boat which pumps water upward through a mud pump connected below to flush the sand, and a sand content monitoring device is provided at the inlet and outlet ends of the sand conveying pipe. When the sand content is monitored to be lower than the set sand content, the mud boat and the mud pump are moved to other positions with high sand content for flushing the sand, thereby ensuring the rapid filling of the loose sand in the woven bags of the main cofferdam and the filling bags of the auxiliary cofferdam, thereby greatly improving the construction efficiency of the membrane bag cofferdam.

[0023] (4) The present invention installs underwater cameras and GPS positioning modules at the four corners of the main cofferdam woven bag, so as to grasp the movement and positioning of the main cofferdam woven bag underwater. When the main cofferdam woven bag deviates from the positioned position, the position of the main cofferdam woven bag can be adjusted in time by using a traction rope to ensure the accurate positioning construction of the main cofferdam woven bag.

[0024] (5) In the present invention, the filling ports of the main cofferdam woven bags or the secondary cofferdam filling bags are connected to the filling hopper, so that water can overflow through the filling hopper while the loose sand is being filled and precipitated, thereby achieving the purpose of rapid filling of the loose sand. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the sandwich film bag cofferdam of the present invention.

[0026] Figure 2 It is a structural schematic diagram of the main cofferdam woven bag connected to an underwater camera, a GPS positioning module and a traction rope of the present invention.

[0027] Figure 3 It is a structural schematic diagram of the positioning cone of the present invention.

[0028] Figure 4 It is a structural schematic diagram of the present invention in which the filling hopper and the sand conveying pipe are connected to the main cofferdam woven bag.

[0029] Figure 5 It is a structural schematic diagram of a mud barge filled with loose sand according to the present invention.

[0030] Figure 6 It is a structural schematic diagram of the sand content monitoring device of the present invention connected to the sand conveying pipe.

[0031] Figure numerals: 1-main cofferdam woven bag, 2-back sand, 3-auxiliary cofferdam filling bag, 4-leakage plugging layer, 5-top woven bag, 6-underwater camera, 7-GPS positioning module, 8-traction rope, 9-flexible adhesive sheet, 10-positioning cone, 11-patch stress sensor, 12-spring oscillator, 13-pressure sensor, 14-filling feed hopper, 15-sand conveying pipe, 16-mud boat, 17-mud pump, 18-drainage pipe, 19-switch valve, 20-loose sand filter screen, 21-measuring cylinder, 22-set scale line on the measuring cylinder. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See Figure 1 , a strong anti-permeability construction method for sandwich membrane bag cofferdams suitable for sandy soil areas, specifically including the following steps:

[0034] (1) Laying out the lines, positioning and cleaning: Position the bottom edge lines of the main cofferdam filling bags and the auxiliary cofferdam filling bags of the sandwich film bag cofferdam, clean the laying area, and clean up the corrosive debris and weeds that are easy to scratch the filling bags; in the filling area, a row of fixed piles (Ø48×3.5mm, 6m long steel pipes) are driven 3-5m away from the main cofferdam woven bag on both sides of the embankment. The fixed piles are buried 2 meters deep in the soil. The distance between two adjacent fixed piles is 10m, which is about 1 / 3 of the length of the main cofferdam woven bag. The head, middle and tail of the main cofferdam woven bag along the length direction are fixed to a row of fixed piles with nylon ropes;

[0035] (2) Paving of the main cofferdam woven bag: The main cofferdam woven bag 1 includes five layers. The widths of the five layers of the main cofferdam woven bag 1 from bottom to top are 30m, 21m, 16m, 11m and 6m respectively. The lengths of the five layers of the main cofferdam woven bag 1 are the same. The splicing seams of the main cofferdam woven bag 1 are nylon threads. Three layers are folded at the seams. The seam width is 5cm. Three seams are sewn (one seam is sewn first, and then two seams are sewn after folding). The strength after sewing is not less than 70% of the strength of the original geotextile. Geotextiles are sewn on the top and bottom surfaces of each layer of the main cofferdam woven bag 1. Each geotextile is 500mm long, 50mm wide, and 3m apart in the length direction.

[0036] See Figure 2 , each layer of the main cofferdam woven bag 1 is connected with a sand conveying pipe 15, and the loose sand is filled into each layer of the main cofferdam woven bag 1 through the sand conveying pipe 15. After each layer of the main cofferdam woven bag 1 is filled and consolidated, the main cofferdam woven bag 1 of the previous layer continues to be filled. An underwater camera 6 and a GPS positioning module 7 are installed at the four corners of each layer of the main cofferdam woven bag 1. A traction rope 8 is connected to the four corners of each layer of the main cofferdam woven bag 1. The underwater camera 6 and the GPS positioning module 7 are connected to the remote monitor through wireless communication. The underwater camera 6 is used to monitor the moving image of the main cofferdam woven bag 1, and the GPS positioning module 7 is used to collect the coordinate information of the four corners of the main cofferdam woven bag 1. When the remote monitor detects that the four corners of the main cofferdam woven bag 1 deviate from the set point coordinates, the position of the main cofferdam woven bag 1 is adjusted by the traction rope 8;

[0037] (3) When all five layers of main cofferdam woven bags 1 are filled, backing sand 2 is filled on the water-facing surface of the main cofferdam woven bags 1. The safety slope ratio of the backing sand 2 on the water-facing surface after filling is 1:10;

[0038] (4) After the backing sand 2 is paved, multi-layer auxiliary cofferdam filling bags 3 are paved on the outer side of the back water surface of the five-layer main cofferdam woven bag 1. The width of the multi-layer auxiliary cofferdam filling bags 3 is equal. The multi-layer auxiliary cofferdam filling bags 3 are arranged obliquely from bottom to top. The axial direction of the inclination of the multi-layer auxiliary cofferdam filling bags 3 is consistent with the axial direction of the inclination of the back water surface of the five-layer main cofferdam woven bag 1; the auxiliary cofferdam filling bags 3 are directly constructed on the ground, so there is no need to install underwater cameras 6 and GPS positioning modules 7 at the four corners of the auxiliary cofferdam filling bags 3;

[0039] (5) After the multi-layer secondary cofferdam filling bag 3 is filled, a layer of waterproof geotextile is laid at the bottom of the area between the five-layer main cofferdam woven bag 1 and the multi-layer secondary cofferdam filling bag 3, and the waterproof geotextile is laid on the plugging layer 4. The height of the backing sand, the five-layer main cofferdam woven bag 1, the multi-layer secondary cofferdam filling bag 3 and the top of the plugging layer 4 are consistent;

[0040] (6) After the plugging layer 4 is paved, a top pressing woven bag 5 is laid on the top surface of the plugging layer 4, and the two ends of the top pressing woven bag 5 in the width direction are respectively placed on the top of the five-layer main cofferdam woven bag 1 and the top of the multi-layer auxiliary cofferdam filling bag 3, thereby forming a sandwich film bag cofferdam consisting of the main cofferdam woven bag 1, backing sand, auxiliary cofferdam filling bag 3, plugging layer 4 and top pressing woven bag 5.

[0041] See Figure 3When five layers of main cofferdam woven bags 1 and multiple layers of auxiliary cofferdam filling bags 3 are laid, a positioning cone 10 is attached to the bottom surface of each layer of main cofferdam woven bags 1 or each layer of auxiliary cofferdam filling bags 3 near the four corners through a flexible adhesive sheet 9. The positioning cone 10 is a hollow structure with an open top. The upper part of the positioning cone 10 is a cylindrical structure and the lower part is an inverted cone structure. The outer wall of the upper part of the positioning cone 10 is completely covered with a patch stress sensor 11. The interior of the positioning cone 10 is provided with a spring oscillator 12 and a pressure sensor 13. The pressure sensor 13 is provided with a spring oscillator 12 and a pressure sensor 13. The force sensor 13 is fixed to the tip of the positioning cone 10, the bottom end of the spring oscillator 12 is connected to the pressure sensor 13, the top end of the spring oscillator 12 extends from the top end of the positioning cone 10 and is fixedly connected to the bottom surface of the main cofferdam woven bag 1, the pressure sensor 13 and the patch stress sensor 11 are connected to the remote monitor through wireless communication; when each layer of the main cofferdam woven bag 1 or each layer of the auxiliary cofferdam filling bag 3 is filled with loose sand, the four corners of the main cofferdam woven bag 1 or the auxiliary cofferdam filling bag 3 will expand and When the positioning cone 10 is inserted into the sand at the bottom of the riverbed, or into the main cofferdam woven bag 1 or the secondary cofferdam filling bag 3 of the next layer, the four corners of the main cofferdam woven bag 1 or the secondary cofferdam filling bag 3 will squeeze the top of the spring vibrator 12, and the top of the spring vibrator 12 will be squeezed into the inside of the positioning cone 10. At this time, the pressure sensor 13 senses the pressure signal and transmits it to the remote monitor, and the remote monitor displays the signal that the positioning cone 10 has been inserted; when the collection surface of the patch stress sensor 11 is completely in contact with the sand at the bottom of the riverbed, or When it contacts with the loose sand in the next layer of main cofferdam woven bags 1 or auxiliary cofferdam filling bags 3, that is, the positioning cone 10 is completely inserted into the sand at the bottom of the riverbed, or the loose sand in the next layer of main cofferdam woven bags 1 or auxiliary cofferdam filling bags 3, at this time, the main cofferdam woven bags 1 or auxiliary cofferdam filling bags 3 are completely fitted with the sand at the bottom of the riverbed, or with the next layer of main cofferdam woven bags 1 or auxiliary cofferdam filling bags 3, that is, the filling of loose sand is stopped, and the five layers of main cofferdam woven bags 1 or multiple layers of auxiliary cofferdam filling bags 3 are tightly fitted, so as to achieve the purpose of strong anti-seepage.

[0042] See Figure 4 When five layers of main cofferdam woven bags 1 and multiple layers of secondary cofferdam filling bags 3 are laid, a plurality of filling ports are evenly arranged on the top surface of the main cofferdam woven bag 1 or the secondary cofferdam filling bag 3, and the plurality of filling ports are connected with corresponding filling hoppers 14 and sand conveying pipes 15. The lower part of the filling hopper 14 is inserted into the main cofferdam woven bag 1 or the secondary cofferdam filling bag 3 through the filling port, and the outlet end of the sand conveying pipe 15 is inserted into the filling hopper 14. The sand conveying pipe 15 conveys the loose sand in the sand water into the main cofferdam woven bag 1 or the secondary cofferdam filling bag 3 for precipitation. When the loose sand is filled to the top of the main cofferdam woven bag 1 or the secondary cofferdam filling bag 3, the water flows through the filling hopper 14 and overflows;

[0043] See Figure 5The sand conveying pipe 15 is connected to the mud boat 16 (located one hundred meters away from the main cofferdam woven bag 1 or the secondary cofferdam filling bag 3), the bottom of the mud boat 16 is connected to the mud pump 17, the mud boat 16 pumps water upwards to flush the sand through the mud pump 17 connected below, and then uses the sand conveying pipe 15 to fill the sand into the main cofferdam woven bag 1 or the secondary cofferdam filling bag 3. The inlet end of the sand conveying pipe 15 connected to the mud boat 16 and the outlet end connected to the main cofferdam woven bag 1 or the secondary cofferdam filling bag 3 are both provided with a sand content monitoring device;

[0044] See Figure 6 The sand content monitoring device includes a drainage pipe 18 connected to the sand conveying pipe 15 at the top, a switch valve 19 arranged at the top of the drainage pipe 18, a loose sand filtering screen 20 (200 mesh) arranged at the bottom of the drainage pipe 18, and a measuring cylinder 21. The bottom of the drainage pipe 18 is inserted into the measuring cylinder 21. The measuring cylinder 21 is marked with a set scale line 22 (500ml). The horizontal height of the set scale line 22 is higher than the horizontal height of the bottom of the drainage pipe 18. When monitoring the sand content, open the valve 19. The valve 19 is switched on and off, and the sand and water in the sand conveying pipe 15 enter the drainage pipe 18. The larger loose sand particles are intercepted by the loose sand filter screen 20, and the water flows into the metering cylinder 21. When the water flows to the set scale line of the metering cylinder 21, the switch valve 19 is closed, and then the metering cylinder 21 is separated from the drainage pipe 18. At this time, the water capacity in the metering cylinder 21 is recorded as M. The sand and water capacity corresponding to the set scale line is 500ml, and the volume of loose sand in the sand and water is (500-M)ml, so the sand content is When the sand content monitoring device detects that the sand content is lower than the set sand content, the mud ship 16 and the mud pump 17 are moved to other locations with high sand content for sand flushing.

[0045] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A strong anti-permeability construction method for sandwich film bag cofferdams suitable for sandy soil areas, characterized by: The specific steps include: (1) Laying out, positioning and cleaning: Position the laying bottom edge of the main cofferdam filling bag and the auxiliary cofferdam filling bag of the sandwich film bag cofferdam, and clean the laying area; (2) Paving and filling of the main cofferdam woven bags: The main cofferdam woven bags include multiple layers, and the width gradually decreases from bottom to top. Each layer of the main cofferdam woven bags is connected to a sand conveying pipe, and loose sand is filled into each layer of the main cofferdam woven bags through the sand conveying pipe. After each layer of the main cofferdam woven bags is filled and consolidated, the main cofferdam woven bags of the previous layer are continued to be filled. An underwater camera and a GPS positioning module are installed at the four corners of each layer of the main cofferdam woven bags. A traction rope is connected to the four corners of each layer of the main cofferdam woven bags. The underwater camera and the GPS positioning module are connected to the remote monitor through wireless communication. The underwater camera is used to monitor the moving image of the main cofferdam woven bags, and the GPS positioning module is used to collect the coordinate information of the four corners of the main cofferdam woven bags. When the remote monitor detects that the four corners of the main cofferdam woven bags deviate from the set point coordinates, the position of the main cofferdam woven bags is adjusted through the traction rope; (3) Backing sand filling: When all the multi-layer main cofferdam woven bags are filled, backing sand is filled on the water-facing surface of the main cofferdam woven bags. The safety slope ratio of the backing sand on the water-facing surface after filling is 1:8-12; (4) Paving of the secondary cofferdam filling bags: After the backing sand is paved, multi-layer secondary cofferdam filling bags are laid on the outer side of the backwater surface of the multi-layer main cofferdam woven bags. The width of the multi-layer secondary cofferdam filling bags is equal. The multi-layer secondary cofferdam filling bags are arranged obliquely from bottom to top. The axial direction of the inclination of the multi-layer secondary cofferdam filling bags is consistent with the axial direction of the inclination of the backwater surface of the multi-layer main cofferdam woven bags; (5) Paving and filling of the plugging layer: After the multi-layer auxiliary cofferdam filling bags are filled, a layer of waterproof geotextile is laid at the bottom of the area between the multi-layer main cofferdam woven bags and the multi-layer auxiliary cofferdam filling bags, and the plugging layer is laid on the waterproof geotextile. The height of the backing sand, the multi-layer main cofferdam woven bags, the multi-layer auxiliary cofferdam filling bags and the top of the plugging layer is consistent; (6) Laying of top-pressing woven bags: After the plugging layer is paved, a top-pressing woven bag is laid on the top surface of the plugging layer, and the two ends of the top-pressing woven bag in the width direction are respectively placed on the top of the multi-layer main cofferdam woven bag and the top of the multi-layer auxiliary cofferdam filling bag, thereby forming a sandwich film bag cofferdam consisting of the main cofferdam woven bag, backing sand, auxiliary cofferdam filling bag, plugging layer and top-pressing woven bag; When the multi-layer main cofferdam woven bags and the multi-layer auxiliary cofferdam filling bags are laid, a positioning cone is pasted on the bottom surface of each layer of the main cofferdam woven bags or each layer of the auxiliary cofferdam filling bags near the four corners, and a patch type stress sensor is arranged on the outer wall of the positioning cone. The patch type stress sensor is connected to the remote monitor through wireless communication. When each layer of the main cofferdam woven bags or each layer of the auxiliary cofferdam filling bags is filled with loose sand, the positions of the four corners of the main cofferdam woven bags or the auxiliary cofferdam filling bags will expand and expand, and the positioning cone will be inserted into the sand at the bottom of the riverbed, or the main cofferdam woven bags or auxiliary cofferdam filling bags of the next layer When the collection surface of the patch stress sensor is completely in contact with the sand at the bottom of the riverbed, or with the loose sand in the next layer of main cofferdam woven bags or auxiliary cofferdam filling bags, the positioning cone is completely inserted into the sand at the bottom of the riverbed, or the loose sand in the next layer of main cofferdam woven bags or auxiliary cofferdam filling bags. At this time, the main cofferdam woven bags or auxiliary cofferdam filling bags are completely in contact with the sand at the bottom of the riverbed, or with the next layer of main cofferdam woven bags or auxiliary cofferdam filling bags, that is, the filling of loose sand is stopped, and the close fit of multiple layers of main cofferdam woven bags or multiple layers of auxiliary cofferdam filling bags is achieved, so as to achieve the purpose of strong anti-seepage.

2. The strong anti-permeability construction method of the sandwich film bag cofferdam suitable for sandy soil areas according to claim 1 is characterized by: The positioning cone is a hollow structure with an opening at the top. A spring vibrator and a pressure sensor are arranged inside the positioning cone. The pressure sensor is fixed at the tip of the positioning cone. The bottom end of the spring vibrator is connected to the pressure sensor. The top end of the spring vibrator extends from the top end of the positioning cone and is fixedly connected to the bottom surface of the main cofferdam woven bag. The pressure sensor is connected to the remote monitor through wireless communication. When each layer of the main cofferdam woven bag or each layer of the auxiliary cofferdam filling bag is filled with loose sand, the four corners of the main cofferdam woven bag or the auxiliary cofferdam filling bag will swell and expand, and when the positioning cone is inserted into the sand at the bottom of the riverbed, or into the main cofferdam woven bag or the auxiliary cofferdam filling bag of the next layer, the four corners of the main cofferdam woven bag or the auxiliary cofferdam filling bag will squeeze the top end of the spring vibrator, and the top end of the spring vibrator will squeeze into the interior of the positioning cone. At this time, the pressure sensor senses the pressure signal and transmits it to the remote monitor, and the remote monitor displays a signal that the positioning cone has been inserted.

3. The strong anti-permeability construction method of the sandwich film bag cofferdam suitable for sandy soil areas according to claim 1 is characterized by: The upper part of the positioning cone is a cylindrical structure, and the lower part is an inverted cone structure. The patch-type stress sensor is completely covered on the outer wall of the upper part of the positioning cone.

4. The strong anti-permeability construction method of the sandwich film bag cofferdam suitable for sandy soil areas according to claim 1 is characterized by: The sand conveying pipe is connected to the mud boat, the bottom of the mud boat is connected to the mud pump, the mud boat pumps water upward to flush the sand through the mud pump connected below, and then uses the sand conveying pipe to fill the sand into the main cofferdam woven bag or the auxiliary cofferdam filling bag. The inlet end of the sand conveying pipe connected to the mud boat and the outlet end connected to the main cofferdam woven bag or the auxiliary cofferdam filling bag are both provided with a sand content monitoring device, which includes a drainage pipe with a top connected to the sand conveying pipe, a switch valve arranged at the top of the drainage pipe, a loose sand filtering screen arranged at the bottom of the drainage pipe, and a measuring cylinder. Insert the part into the measuring cylinder. The measuring cylinder is marked with a set scale line. The horizontal height of the set scale line is higher than the horizontal height of the bottom of the drainage tube. When monitoring the sand content, open the switch valve, the sand water in the sand conveying pipe enters the drainage tube, the larger loose sand particles are intercepted by the loose sand filter screen, and the water flows into the measuring cylinder. When the water flow reaches the set scale line of the measuring cylinder, close the switch valve, and then separate the measuring cylinder from the drainage tube. At this time, the water capacity in the measuring cylinder is recorded as M, and the sand water capacity corresponding to the set scale line is N. The volume of loose sand in the sand water is NM, and the sand content When the sand content monitoring device detects that the sand content is lower than the set sand content, the mud boat and the mud pump are moved to other locations with high sand content for sand flushing.

5. The strong anti-permeability construction method of the sandwich film bag cofferdam suitable for sandy soil areas according to claim 1 is characterized by: A plurality of filling ports are evenly arranged on the top surface of the main cofferdam woven bag or the auxiliary cofferdam filling bag, and the plurality of filling ports are connected with corresponding filling hoppers and sand conveying pipes. The lower part of the filling hopper is inserted into the main cofferdam woven bag or the auxiliary cofferdam filling bag through the filling port, and the outlet end of the sand conveying pipe is inserted into the filling hopper. The sand conveying pipe conveys the loose sand in the sand water into the main cofferdam woven bag or the auxiliary cofferdam filling bag for sedimentation. When the loose sand is filled to the top of the main cofferdam woven bag or the auxiliary cofferdam filling bag, the water flows through the filling hopper and overflows.

6. The strong anti-permeability construction method of sandwich film bag cofferdam suitable for sandy soil areas according to claim 1 is characterized by: Before laying each layer of the main cofferdam woven bags, a row of fixed piles are driven in the filling area along both sides of the embankment core at a distance of 3-5m from the main cofferdam woven bags, and the head, middle and tail of the main cofferdam woven bags along the length direction are fixed to the row of fixed piles with nylon ropes.

7. The strong anti-permeability construction method of sandwich film bag cofferdam suitable for sandy soil areas according to claim 1 is characterized by: The top surface and bottom surface of each layer of main cofferdam woven bags or auxiliary cofferdam filling bags are sewn with geotextile belts.

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