Seepage-proofing joint structure for casing milling of underground diaphragm wall in deep sea mud stratum and construction method

Abstract

The invention discloses a milling anti-seepage joint structure of a deep sea mud stratum underground diaphragm wall and a construction method. The milling anti-seepage joint structure comprises an occlusion tooth end face, a groove guide pipe, an electroosmosis anode water stop belt, a flocculation precipitation pipe, a gas lift pipe and a one-way flow channel. An electro-osmosis anode and a water stop belt are integrated, a seepage path is prolonged through an occlusion tooth end face and a groove guide pipe, the seepage path is cut off by the water stop belt, and electro-osmosis initiative water prevention is achieved, so that the anti-seepage effect of the multi-layer milling anti-seepage joint is achieved; the construction method comprises the steps of groove section division, grabbing and milling combined process groove forming, pre-pouring groove concrete pouring, casing milling operation, meshing tooth end face brushing, flocculent precipitation, gas lift reverse circulation, post-pouring groove concrete pouring, grouting plugging and electroosmosis system debugging. By combining flocculent precipitation with a gas lift reverse circulation process, the desalting and sludge removing efficiency is improved, and the problem of salt erosion of a milling anti-seepage joint structure is effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of underground engineering structure construction, and in particular to a milling anti-seepage joint structure of an underground continuous wall sleeve in a deep-sea mud stratum and a construction method. Background Art

[0002] Deep-sea mud formations are a special geological environment mainly distributed in the deep waters of the South China Sea and the eastern coastal shelf of my country. The formation components are mainly biological origin and fine-grained non-biological components of deep-sea sediments, and are characterized by high water content, complex chemical composition and high salinity.

[0003] When constructing underground continuous walls in deep-sea mud formations, due to the high water content, low-strength soil characteristics and trench wall stability control requirements, it is usually necessary to adopt a construction process of segmented trenching and segmented pouring. The resulting joints between wall segments become a key link affecting the integrity, impermeability and structural safety of the wall. Traditional joint technologies such as lock pipe joints, I-beam joints or cross steel plate joints are prone to trench wall collapse, joint leakage, and insufficient salt resistance of steel. Although the existing milling anti-seepage joint technology improves the shear strength of the underground continuous wall through serrated bite, it still has the following shortcomings in deep-sea mud formations: 1) Soluble salt substances will corrode the concrete, resulting in reduced concrete strength and durability at the joint, affecting the water-stopping performance of the joint and the safety of the overall structure; 2) The construction quality is difficult to control, and the accumulation of mud residues and retention of salt solutions caused by milling are difficult to detect and deal with, which can easily form a weak interlayer and cause concrete quality degradation and joint damage; 3) The milling anti-seepage joint relies on the wavy surface formed by milling to improve the water-stopping performance, but in saline formations, the crystallization and expansion of salt substances retained in the joint will cause a network of micro-cracks on the interface, which may destroy the sealing of the joint and cause groundwater bypass and leakage; 4) The increase in the depth of the underground continuous wall intensifies the shrinkage deformation of the concrete after pouring, resulting in micro-cracks at the joint under the action of tensile stress, which destroys the sealing of the joint.

[0004] When constructing underground continuous walls in high-salinity strata, the salt problem is usually dealt with by simple mud replacement or chemical additives, which has low desalination efficiency and fails to systematically combine flocculation sedimentation with air lift reverse circulation technology. In the existing construction of casing milling anti-seepage joints, air lift reverse circulation operations are mostly used for slag removal, and no targeted treatment is carried out for the problem of salt erosion.

[0005] When the electro-osmosis method is applied to the waterproofing of underground structures, the electro-osmosis anode is usually arranged in the groove on the concrete surface. Since the efficiency of the groove operation is low and a certain working surface is required, it is difficult to apply it to the waterproofing of the milling waterproof joints of underground continuous wall sleeves. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention applies for a deep-sea mud stratum underground continuous wall sleeve milling anti-seepage joint structure and a construction method, which is beneficial to solving the anti-seepage problem of the underground continuous wall sleeve milling anti-seepage joint structure in a salt corrosion environment.

[0007] The first aspect of the present application discloses a milling anti-seepage joint structure for underground continuous wall in deep-sea mud strata, which is used for connecting the first pouring trough and the later pouring trough of the underground continuous wall. The milling anti-seepage joint structure includes a bite tooth end face, a groove guide pipe, an electric osmosis system, a flocculation sedimentation pipe, an air lift pipe and a one-way flow channel; the bite tooth end face is a continuous curved groove formed by milling operation on the connecting end face of the concrete of the first pouring trough; the groove guide pipe is vertically embedded in the concrete of the first pouring trough throughout its length, and the exposed part after the milling operation forms an arc groove to guide the first pouring A mutually interlocking structure is formed between the trough concrete and the post-cast trough concrete; the electro-osmosis system includes an electro-osmosis anode waterstop, an electro-osmosis cathode rod, a humidity sensor, a microcomputer control module, a switching power supply, an adjustable frequency pulse signal generator and a conductor; the flocculation sedimentation pipe and the gas lift pipe are vertically pre-buried in the first-cast trough concrete, and are connected to the groove guide pipe through the one-way flow channel; the one-way flow channel adopts a check valve structure, which only allows the medium to flow from the flocculation sedimentation pipe or the gas lift pipe to the groove guide pipe.

[0008] Preferably, in the electro-osmosis system, one end of the electro-osmosis anode waterstop is vertically extended and pre-buried in the pre-cast trough concrete, and the other end is vertically extended and freely extends into the groove guide tube, the electro-osmosis anode waterstop adopts an EPDM rubber waterstop, embedded with a flat titanium wire mesh that is continuously bent and extended in an S shape; the electro-osmosis cathode rod is vertically buried in the surrounding strata of the underground continuous wall, composed of a pure titanium conductive core and a graphite wrapping layer, and connected to the electro-osmosis anode waterstop through a wire; the humidity sensor is arranged on the electro-osmosis anode waterstop, for obtaining the humidity of the end face of the bite tooth and transmitting the signal to the microcomputer control module; the microcomputer control module controls the switching power supply and the adjustable frequency pulse signal generator according to the humidity signal; the adjustable frequency pulse signal generator is used to generate a pulse voltage; the pulse voltage generated by the cooperation of the electro-osmosis anode waterstop and the electro-osmosis cathode rod can drive the water in the microcracks on the end face of the bite tooth to migrate toward the direction of the electro-osmosis cathode rod.

[0009] The second aspect of the present application discloses a construction method for a deep-sea mud stratum underground continuous wall sleeve milling anti-seepage joint structure, comprising the following steps: S1. Slot segment division: The underground continuous wall is divided into several slot segments and the construction sequence of each slot segment is determined according to the principle of interval construction, so that the concrete of each slot segment can reduce the negative impact caused by its own shrinkage deformation after stress release; the slot segment is divided into pre-cast slots and post-cast slots according to the construction sequence; the slot segment length is determined according to the resistance of the concrete of each slot segment to temperature shrinkage stress; S2. Grooving by combining grabbing and milling: In view of the fact that deep-sea mud strata are soft on the top and hard on the bottom, a hydraulic grab groover is first used to grab and remove the shallow soft strata, and then a groove milling machine is used to mill out the deep hard strata until the groove depth is reached; mud wall protection is used during the groove forming process; S3. Casting of the precast trough concrete: fix the pre-connected groove guide pipe, flocculation sedimentation pipe, gas lift pipe, one-way flow channel and electro-osmosis anode water stop in the precast trough, temporarily block the pipe port, and then cast the precast trough concrete; S4, milling operation: after the construction of the first pouring slot is completed and before the construction of the second pouring slot, the milling operation is carried out; the 15cm concrete at both ends of the first pouring slot is milled away by a slot milling machine to form a sawtooth-shaped interlocking tooth end face, and the groove guide pipe and the electro-osmosis anode water stop pre-buried in the concrete of the first pouring slot are exposed, and the exposed part of the groove guide pipe forms a vertically long semicircular groove; the slot milling machine is accurately positioned through the positioning frame to ensure that the electro-osmosis anode water stop is not damaged; S5, cleaning the meshing tooth end surface: lifting the wall brush by a crane, brushing the meshing tooth end surface up and down, and removing concrete debris and sundries on the meshing tooth end surface, until there is no concrete debris or sundries attached to the wall brush after the wall brush is lifted and leaves the groove section; S6, flocculation and sedimentation: Flocculant and Ca(OH)2 suspension are injected into the bottom of the tank in sequence through the flocculation and sedimentation pipe. The flocculant promotes the coagulation and sedimentation of fine solid impurities in the mud, and then the Ca(OH)2 suspension is injected into the bottom of the tank in sequence. 2+ SO4 seeping into the mud from the formation 2- Precipitation occurs, and the precipitation reaction expression is Ca 2+ +SO4 2- →CaSO4↓; Ca(OH)2 solution follows the SO4 of the mud in the tank 2- The concentration determines the theoretical dosage; S7, air lift reverse circulation: start the air compressor and inject high-pressure air into the bottom of the tank through the air lift pipe. The air and mud are mixed to form a low-density gas-liquid mixture, which drives the mud residue at the bottom of the tank, the waste liquid and waste residue after flocculation and precipitation to the ground. After being treated by the separation system, the clean mud is returned to the tank for recycling until the SO4 2- , Cl - Until the concentration meets the requirements; S8, post-casting groove concrete pouring: During the pouring operation, the buried depth of the conduit and the height difference of adjacent conduits are controlled to prevent mud from being trapped in the sleeve milling anti-seepage joint structure; the concrete forms a mutually interlocking structure at the groove guide pipe and wraps the electro-osmosis anode water stop; S9, grouting and plugging: pressure grouting is performed on the end surface of the bite tooth through the flocculation sedimentation pipe and the air lift pipe to fill the micro cracks existing on the end surface of the bite tooth; S10. Debugging of the electro-osmosis system: After the electro-osmosis system is installed, the electro-osmosis anode waterstop and the electro-osmosis cathode rod cooperate with each other to generate a pulse voltage, and the data changes of the humidity sensor are used to determine whether the electro-osmosis system is operating normally.

[0010] Preferably, in step S1, the slot length L Satisfies the following expression:

[0011] in, E is the elastic modulus of concrete, N / m 2 ; D is the depth of the slot, m; B is the slot width, m; C is the interlayer horizontal resistance coefficient between concrete and deep-sea mud strata, N / m 3 , and according to the different interaction characteristics between concrete and deep-sea mud formations, C The value range is 1×10 8 N / m 3 ~1×10 9 N / m 3 ; f t is the tensile strength of concrete, N / m 2 ; α is the linear elastic coefficient of concrete, °C -1 ,and α The value range is 1×10 -5 °C -1 ~1.5×10 -5 °C -1 ; T is the temperature difference, °C.

[0012] Preferably, in step S7, the gas lift reverse circulation pressure P Satisfies the following expression:

[0013] in, ρ is the mud density, kg / m 3 ; g is the acceleration due to gravity, m / s 2 ;f is the friction coefficient between the mud and the sidewall, and f The value range of is 0.2~0.5; v is the mud flow rate; B is the slot width.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: in view of the anti-seepage problem of underground continuous wall sleeve milling anti-seepage joint structure in a salt corrosion environment, a deep-sea mud stratum underground continuous wall sleeve milling anti-seepage joint structure and a construction method are disclosed, the sleeve milling anti-seepage joint structure includes a bite tooth end face, a groove guide pipe, an electro-osmosis anode waterstop, a flocculation sedimentation pipe, a gas lift pipe and a one-way flow channel; by integrating the electro-osmosis anode and the waterstop into one, the on-site construction step of grooving the concrete surface is avoided, which is beneficial to improving the construction efficiency and quality of the electro-osmosis anode; according to the humidity of the bite tooth end face monitored by the humidity sensor, a pulse voltage is generated through the cooperation of the electro-osmosis anode waterstop and the electro-osmosis cathode rod, driving the water in the micro-cracks of the bite tooth end face to migrate toward the direction of the electro-osmosis cathode rod, thereby achieving the effect of active waterproofing; through the bite tooth end face and The groove guide pipe extends the seepage path, the water stop strip cuts off the seepage path, and the electro-osmosis active waterproofing achieves a multi-level anti-seepage effect of the sleeve milling anti-seepage joint; the construction method includes slot segmentation, slotting by grabbing and milling combined process, first pouring slot concrete, sleeve milling operation, cleaning the end face of the bite tooth, flocculation sedimentation, air lift reverse circulation, post-casting slot concrete pouring, grouting and plugging, and electro-osmosis system debugging; through reasonable slot segmentation and control of slot segment length, the possibility of micro cracks on the end face of the bite tooth caused by concrete shrinkage stress is reduced; through the combination of flocculation sedimentation and air lift reverse circulation technology, the soluble salt near the end face of the bite tooth is converted into flocculated sediment that is easier to remove, and the air lift reverse circulation technology is used to remove the mud residue at the bottom of the slot, the waste liquid and waste residue after flocculation sedimentation, so as to improve the efficiency of desalting and demud removal, and effectively solve the problem of salt erosion in the sleeve milling anti-seepage joint structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the sleeve milling anti-seepage joint structure before milling shown in an embodiment of the present invention; Figure 2 It is a schematic diagram of the structure of the sleeve milling anti-seepage joint structure after milling shown in an embodiment of the present invention; Figure 3 It is a schematic diagram of the structure of the sleeve milling anti-seepage joint structure after the post-casting trough is cast as shown in an embodiment of the present invention; Figure 4 A schematic diagram of an electro-osmosis anode waterstop shown in an embodiment of the present invention; Figure 5 It is a schematic elevation view of the electro-osmosis direction shown in an embodiment of the present invention; Figure 6It is a flow chart of a construction method of a deep-sea mud stratum underground continuous wall sleeve milling anti-seepage joint structure of the present invention; Figure markings: 11-biting tooth end face, 12-groove guide tube, 13-electro-osmosis anode waterstop, 131-flat titanium wire mesh, 14-electro-osmosis cathode rod, 15-one-way flow channel, 16-flocculation sedimentation tube, 17-gas lift pipe, 18-first pouring trough, 19-second pouring trough, 20-electro-osmosis direction. DETAILED DESCRIPTION

[0016] The following is a more detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and the accompanying drawings so that a person skilled in the art can implement the embodiments after reading the description. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] The first aspect of the present application discloses Figure 1-4 The structure of the milling anti-seepage joint of the underground continuous wall in deep-sea mud strata is shown, which is used for connecting the first pouring groove and the later pouring groove of the underground continuous wall. The milling anti-seepage joint structure includes a bite tooth end face 11, a groove guide pipe 12, an electric osmosis system, a flocculation sedimentation pipe 16, an air lift pipe 17 and a one-way flow channel 15; the bite tooth end face 11 is a continuous curved groove formed by the milling operation on the connecting end face of the concrete of the first pouring groove; the groove guide pipe 12 is vertically embedded in the concrete of the first pouring groove, and the exposed part after the milling operation forms an arc groove to guide the concrete of the first pouring groove and the later pouring groove The concrete forms a mutually interlocking structure; the electro-osmosis system includes an electro-osmosis anode waterstop 13, an electro-osmosis cathode rod 14, a humidity sensor, a microcomputer control module, a switching power supply, an adjustable frequency pulse signal generator and a conductor; the flocculation sedimentation pipe 16 and the gas lift pipe 17 are vertically pre-buried in the pre-cast trough concrete, and are connected to the groove guide pipe 12 through the one-way flow channel 15; the one-way flow channel 15 adopts a check valve with a ball valve structure, which only allows the medium to flow from the flocculation sedimentation pipe 16 or the gas lift pipe 17 to the groove guide pipe 12.

[0018] In the specific implementation, in the electro-osmosis system, one end of the electro-osmosis anode waterstop 13 is vertically extended and pre-buried in the pre-cast trough concrete, and the other end is vertically extended and freely extends into the groove guide pipe 12. The electro-osmosis anode waterstop 13 adopts EPDM rubber waterstop, and is embedded with a flat titanium wire mesh 131 that is continuously bent and extended in an S shape; the electro-osmosis cathode rod 14 is vertically buried in the surrounding stratum of the underground continuous wall, and is composed of a pure titanium conductive core and a graphite wrapping layer, and is connected to the electro-osmosis anode waterstop 13 through a wire; the wet The humidity sensor is arranged on the electro-osmosis anode waterstop 13, and is used to obtain the humidity of the end face 11 of the meshing tooth and transmit the signal to the microcomputer control module; the microcomputer control module controls the switching power supply and the adjustable frequency pulse signal generator according to the humidity signal; the adjustable frequency pulse signal generator is used to generate a pulse voltage; the pulse voltage is generated by the cooperation of the electro-osmosis anode waterstop 13 and the electro-osmosis cathode rod 14, which can drive the water in the micro-cracks on the end face of the meshing tooth to migrate toward the direction of the electro-osmosis cathode rod 14.

[0019] In specific implementation, the production process of the electro-permeation anode waterstop 13 is as follows: the titanium wire is weaved into a planar mesh structure with an S-shaped bend and extension, and then it is precisely placed and fixed between two layers of EPDM rubber waterstop, and high temperature and high pressure are applied to achieve firm bonding. Finally, the integrity and uniformity of the planar titanium wire mesh 131 are verified through a conductivity test to ensure that there are no breakpoints or short circuits.

[0020] The second aspect of the present application discloses Figure 5-6 The construction method of a deep-sea mud stratum underground continuous wall sleeve milling anti-seepage joint structure shown includes the following steps: S1. Slot segment division: The underground continuous wall is divided into several slot segments and the construction sequence of each slot segment is determined according to the principle of interval construction, so that the concrete of each slot segment can reduce the negative impact caused by its own shrinkage deformation after stress release; the slot segment is divided into pre-cast slots and post-cast slots according to the construction sequence; the slot segment length is determined according to the resistance of the concrete of each slot segment to temperature shrinkage stress; the slot segment length L Satisfies the following expression: (1) in, E is the elastic modulus of concrete, N / m 2 ; D is the depth of the slot, m; B is the slot width, m; C is the interlayer horizontal resistance coefficient between concrete and deep-sea mud strata, N / m 3 , and according to the different interaction characteristics between concrete and deep-sea mud formations, C The value range is 1×10 8N / m 3 ~1×10 9 N / m 3 ; f t is the tensile strength of concrete, N / m 2 ; α is the linear elastic coefficient of concrete, °C -1 ,and α The value range is 1×10 -5 °C -1 ~1.5×10 -5 °C -1 ; T is the temperature difference, °C; In specific implementation, the elastic modulus of concrete E 3×10 10 N / m 2 , slot depth D The width of the trench is 54.5m. B The horizontal resistance coefficient between the concrete and the deep-sea mud layer is 1m. C For 10 8 N / m 3 , the tensile strength of concrete f t 2×10 6 N / m 2 , the linear elastic coefficient of concrete α 1×10 -5 °C -1 , temperature difference T is 30°C; slot length L According to formula (1), the calculation is as follows: (2) That is, the required slot length L Not more than 6.76m, the length of the post-casting trough section planned in the specific implementation L 6m; S2. Grooving by combining grabbing and milling: In view of the fact that deep-sea mud strata are soft on the top and hard on the bottom, a hydraulic grab groover is first used to grab and remove the shallow soft strata, and then a groove milling machine is used to mill out the deep hard strata until the groove depth is reached; mud wall protection is used during the groove forming process; S3. Casting of the precast trough concrete: fix the pre-connected groove guide pipe, flocculation sedimentation pipe, gas lift pipe, one-way flow channel and electro-osmosis anode water stop in the precast trough, temporarily block the pipe port, and then cast the precast trough concrete; S4, milling operation: after the construction of the first pouring slot is completed and before the construction of the second pouring slot, the milling operation is carried out; the concrete of 15 cm at both ends of the first pouring slot is milled away by a milling machine to form a serrated meshing tooth end face 11, and the groove guide pipe 12 and the electro-osmosis anode water stop 13 pre-buried in the concrete of the first pouring slot are exposed, and the exposed part of the groove guide pipe 12 forms a vertically long semicircular groove; the milling machine is accurately positioned by a positioning frame to ensure that the electro-osmosis anode water stop 13 is not damaged; S5, cleaning the meshing tooth end surface: lifting the wall brush by a crane, brushing the meshing tooth end surface 11 up and down, and removing concrete debris and sundries on the meshing tooth end surface 11, until there is no concrete debris or sundries attached to the wall brush after the wall brush is lifted and leaves the groove section; S6, flocculation and sedimentation: polyacrylamide flocculant and Ca(OH)2 suspension are injected into the bottom of the tank in sequence through the flocculation and sedimentation pipe 16, and the fine solid impurities in the mud are precipitated by the polyacrylamide flocculant, and then the Ca(OH)2 suspension is 2+ SO4 seeping into the mud from the formation 2- Precipitation occurs, and the precipitation reaction expression is Ca 2+ +SO4 2- →CaSO4↓; Ca(OH)2 solution follows the SO4 of the mud in the tank 2- The concentration determines the theoretical dosage; S7, air lift reverse circulation: Start the air compressor and inject high-pressure air into the bottom of the tank through the air lift pipe 17. The air and mud are mixed to form a low-density gas-liquid mixture, which drives the mud residue at the bottom of the tank, the waste liquid and waste residue after flocculation and precipitation to the ground. After being treated by the separation system, the clean mud is returned to the tank for recycling until the SO4 2- , Cl - Until the concentration meets the requirements; gas lift reverse circulation pressure P Satisfies the following expression: (3) in, ρ is the mud density, kg / m 3 ; g is the acceleration due to gravity, m / s 2 ; f is the friction coefficient between the mud and the sidewall, and f The value range of is 0.2~0.5; v is the mud flow rate, m / s; In the specific implementation, the mud density ρ 1200kg / m 3 , the acceleration due to gravity g 9.8 m / s 2 , the friction coefficient between the mud and the sidewall f is 0.2, mud flow ratev is 1m / s, the depth of the slot D The width of the trench is 54.5m. B 1m, slot length L 6m; gas lift reverse circulation pressure P According to formula (3), the calculation is as follows: (4) That is, the required gas lift reverse circulation pressure P It is 0.64MPa.

[0021] S8, pouring of post-casting groove concrete: during the pouring operation, the buried depth of the conduit and the height difference of adjacent conduits are controlled to prevent mud from being trapped in the sleeve milling anti-seepage joint structure; the concrete forms a mutually interlocking structure at the groove guide pipe 12 and wraps the electro-osmosis anode water stop 13; S9, grouting and plugging: pressure grouting is performed on the bite tooth end surface 11 through the flocculation sedimentation pipe 16 and the air lift pipe 17 to fill the micro cracks existing on the bite tooth end surface 11; S10. Debugging of the electro-osmosis system: After the electro-osmosis system is laid out, the electro-osmosis anode waterstop 13 and the electro-osmosis cathode rod 14 cooperate with each other to generate a pulse voltage, and the data changes of the humidity sensor are used to determine whether the electro-osmosis system is operating normally; in specific implementation, when the humidity data measured by the humidity sensor continues to decrease and the downward trend is synchronized with the pulse voltage output, it indicates that the electro-osmosis system is operating normally, and the electro-osmosis direction 20 is from the electro-osmosis anode waterstop 13 to the soil side of the underground continuous wall, and the electric field drives the moisture to migrate to the cathode; when the humidity data measured by the humidity sensor does not decrease significantly or is not synchronized with the pulse voltage output, it indicates that there is an abnormality in the operation of the electro-osmosis system, which should be checked and handled in time.

[0022] It can be seen that by integrating the electro-osmosis anode and the waterstop, the on-site construction step of grooving the concrete surface is avoided, which is conducive to improving the construction efficiency and quality of the electro-osmosis anode; according to the humidity of the bite tooth end face monitored by the humidity sensor, a pulse voltage is generated through the cooperation of the electro-osmosis anode waterstop and the electro-osmosis cathode rod, driving the water in the micro-cracks of the bite tooth end face to migrate toward the direction of the electro-osmosis cathode rod, thereby achieving the effect of active waterproofing; the seepage path is extended by the bite tooth end face and the groove guide pipe, the seepage path is cut off by the waterstop, and the electro-osmosis active waterproofing is achieved, so as to achieve a multi-level anti-seepage effect of the sleeve milling anti-seepage joint; through reasonable slot segment division and control of slot segment length, the possibility of micro-cracks on the bite tooth end face caused by concrete shrinkage stress is reduced; through the combination of flocculation sedimentation and air lift reverse circulation process, the soluble salt near the bite tooth end face is converted into flocculated sediment that is easier to remove, and the gas lift reverse circulation process is used to remove the mud residue at the bottom of the slot, the waste liquid and waste residue after flocculation sedimentation, improve the efficiency of desalting and mud residue removal, and effectively solve the salt erosion problem of the sleeve milling anti-seepage joint structure.

[0023] The above are one or more embodiments of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A milling anti-seepage joint structure of underground continuous wall sleeve in deep-sea mud strata, characterized in that: Used for connecting the first pouring trough and the second pouring trough of an underground continuous wall, it comprises an engaging tooth end face, a groove guide pipe, an electro-osmosis system, a flocculation and sedimentation pipe, an air lift pipe and a one-way flow channel; the engaging tooth end face is a continuous curved groove formed by milling operation on the connecting end face of the first pouring trough concrete; the groove guide pipe is vertically embedded in the first pouring trough concrete, and the exposed part after the milling operation forms an arc groove, which guides the first pouring trough concrete and the second pouring trough concrete to form a mutually engaged structure; the electro-osmosis system comprises an electro-osmosis anode water stop, an electro-osmosis cathode rod, a humidity sensor, a microcomputer control module, a switching power supply, a frequency-adjustable pulse signal generator and a conductor; the flocculation and sedimentation pipe and the air lift pipe are vertically embedded in the first pouring trough concrete, and are connected to the groove guide pipe through the one-way flow channel; the one-way flow channel adopts a check valve structure, which only allows the medium to flow from the flocculation and sedimentation pipe or the air lift pipe to the groove guide pipe.

2. The deep-sea mud stratum underground continuous wall sleeve milling anti-seepage joint structure according to claim 1 is characterized in that: In the electro-osmosis system, one end of the electro-osmosis anode waterstop is vertically extended and pre-buried in the pre-cast trough concrete, and the other end is vertically extended and freely extends into the groove guide pipe. The electro-osmosis anode waterstop adopts EPDM rubber waterstop, embedded with a flat titanium wire mesh that is continuously bent and extended in an S shape; the electro-osmosis cathode rod is vertically buried in the surrounding stratum of the underground continuous wall, composed of a pure titanium conductive core and a graphite wrapping layer, and connected to the electro-osmosis anode waterstop through a wire; the humidity sensor is arranged on the electro-osmosis anode waterstop, for obtaining the humidity of the end face of the occluding tooth and transmitting the signal to the microcomputer control module; the microcomputer control module controls the switching power supply and the adjustable frequency pulse signal generator according to the humidity signal; the adjustable frequency pulse signal generator is used to generate a pulse voltage.

3. A construction method for a deep-sea mud stratum underground continuous wall sleeve milling anti-seepage joint structure, characterized in that: A deep-sea mud stratum underground continuous wall sleeve milling anti-seepage joint structure for use in any one of claims 1-2, comprising the following steps: S1. Slot segment division: The underground continuous wall is divided into several slot segments and the construction sequence of each slot segment is determined according to the principle of interval construction, so that the concrete of each slot segment can reduce the negative impact caused by its own shrinkage deformation after stress release; the slot segment is divided into pre-cast slots and post-cast slots according to the construction sequence; the slot segment length is determined according to the resistance of the concrete of each slot segment to temperature shrinkage stress; S2. Grooving by combining grabbing and milling: In view of the fact that deep-sea mud strata are soft on the top and hard on the bottom, a hydraulic grab groover is first used to grab and remove the shallow soft strata, and then a groove milling machine is used to mill out the deep hard strata until the groove depth is reached; mud wall protection is used during the groove forming process; S3. Casting of the precast trough concrete: fix the pre-connected groove guide pipe, flocculation sedimentation pipe, gas lift pipe, one-way flow channel and electro-osmosis anode water stop in the precast trough, temporarily block the pipe port, and then cast the precast trough concrete; S4, milling operation: after the construction of the first pouring slot is completed and before the construction of the second pouring slot, the milling operation is carried out; the 15cm concrete at both ends of the first pouring slot is milled away by a slot milling machine to form a sawtooth-shaped interlocking tooth end face, and the groove guide pipe and the electro-osmosis anode water stop pre-buried in the concrete of the first pouring slot are exposed, and the exposed part of the groove guide pipe forms a vertically long semicircular groove; the slot milling machine is accurately positioned through the positioning frame to ensure that the electro-osmosis anode water stop is not damaged; S5, cleaning the meshing tooth end surface: lifting the wall brush by a crane, brushing the meshing tooth end surface up and down, and removing concrete debris and sundries on the meshing tooth end surface, until there is no concrete debris or sundries attached to the wall brush after the wall brush is lifted and leaves the groove section; S6, flocculation and sedimentation: Flocculant and Ca(OH)2 suspension are injected into the bottom of the tank in sequence through the flocculation and sedimentation pipe. The flocculant promotes the coagulation and sedimentation of fine solid impurities in the mud, and then the Ca(OH)2 suspension is injected into the bottom of the tank in sequence. 2+ SO4 seeping into the mud from the formation 2- Precipitation occurs; Ca(OH)2 solution is precipitated according to the SO4 2- The concentration determines the theoretical dosage; S7, air lift reverse circulation: start the air compressor and inject high-pressure air into the bottom of the tank through the air lift pipe. The air and mud are mixed to form a low-density gas-liquid mixture, which drives the mud residue at the bottom of the tank, the waste liquid and waste residue after flocculation and precipitation to the ground. After being treated by the separation system, the clean mud is returned to the tank for recycling until the SO4 2- , Cl - Until the concentration meets the requirements; S8, post-casting groove concrete pouring: During the pouring operation, the buried depth of the conduit and the height difference of adjacent conduits are controlled to prevent mud from being trapped in the sleeve milling anti-seepage joint structure; the concrete forms a mutually interlocking structure at the groove guide pipe and wraps the electro-osmosis anode water stop; S9, grouting and plugging: pressure grouting is performed on the end surface of the bite tooth through the flocculation sedimentation pipe and the air lift pipe to fill the micro cracks existing on the end surface of the bite tooth; S10. Debugging of the electro-osmosis system: After the electro-osmosis system is installed, the electro-osmosis anode waterstop and the electro-osmosis cathode rod cooperate with each other to generate a pulse voltage, and the data changes of the humidity sensor are used to determine whether the electro-osmosis system is operating normally.

4. The construction method of a deep-sea mud stratum underground continuous wall sleeve milling anti-seepage joint structure according to claim 3 is characterized in that: In step S1, the slot length L Satisfies the following expression: in, E is the elastic modulus of concrete, N / m 2 ; D is the depth of the slot, m; B is the slot width, m; C is the interlayer horizontal resistance coefficient between concrete and deep-sea mud strata, N / m 3 , and according to the different interaction characteristics between concrete and deep-sea mud formations, C The value range is 1×10 8 N / m 3 ~1×10 9 N / m 3 ; f t is the tensile strength of concrete, N / m 2 ; α is the linear elastic coefficient of concrete, °C -1 ,and α The value range is 1×10 -5 °C -1 ~1.5×10 -5 °C -1 ; T is the temperature difference, °C.

5. The construction method of a deep-sea mud stratum underground continuous wall sleeve milling anti-seepage joint structure according to claim 3 is characterized in that: In step S6, the gas lift reverse circulation pressure P Satisfies the following expression: in, ρ is the mud density, kg / m 3 ; g is the acceleration due to gravity, m / s 2 ; f is the friction coefficient between the mud and the sidewall, and f The value range of is 0.2~0.5; v is the mud flow rate; B is the slot width.

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