Construction method of shoe sleeve type anchor rod and anchor cable below underground water level line

Abstract

The invention relates to a shoe sleeve type anchor rod and anchor cable construction method below an underground water level line. The method comprises the steps that an orifice outburst prevention device is installed at an orifice, and an anchor hole is formed through a pressure maintaining and drainage limiting device and a grouting device; the pressure-maintaining discharge-limiting and grouting device is dismantled, the pressure-maintaining grouting device is used for grouting the bottom area, located in the anchor hole, of the outer sleeve, and a bottom reinforcing area is formed; the pressure maintaining grouting device is dismantled, and the shoe sleeve is installed at the hole bottom of the anchor hole and enters a bottom reinforcing area; an anchor rod body or an anchor cable body extends into the anchor hole from the outer sleeve until the anchor rod body or the anchor cable body is mounted at the boot sleeve, and cement paste is injected into the outer sleeve through a primary grouting pipe of the anchor rod body or the anchor cable body until the outer sleeve is full; a pressure-maintaining drainage-limiting and grouting device is installed, pressure-maintaining grouting is conducted on the interior of the outer sleeve, and in the pressure-maintaining grouting process, the outer sleeve is slowly pulled out of the anchor hole; when the outer sleeve is pulled out of the enclosure structure, quick-setting grout is directly injected through the sleeve under the pressure maintaining condition, an orifice of the hole site is closed, and then the outer sleeve is pulled out.

Description

Technical Field

[0001] The invention relates to the field of foundation pits, deep foundation pits and other underground projects, and in particular to a method for constructing anchor rods and anchor cables in foundation pits, deep foundation pits and other underground projects, and more specifically to a method for constructing anchor rods and anchor cables below a groundwater level. Background Art

[0002] With economic development and the expansion of urban construction, high-rise buildings, large buildings and various underground facilities are increasing, and the scale of foundation pits and other underground projects is also getting larger and larger. In the construction process of underground projects, the support form of "enclosing structure + anchor rods (anchor cables)" is often used.

[0003] In previous support work, the required depth of underground facilities was relatively shallow, perhaps only about 10 meters, while the groundwater level was about 30 meters deep. Therefore, the support effect could be easily achieved by using the traditional enclosure structure combined with the support form of anchor rods or anchor cables. However, as people's environmental awareness increases, the protection measures for groundwater are becoming more mature, and the height of the groundwater level is also increasing year by year. Take Beijing as an example. After the implementation of the South-to-North Water Diversion Project, its groundwater level has increased from the original -30 meters to -10 meters.

[0004] However, with the rise of the groundwater level, the depth of underground construction is required to be deeper and deeper, sometimes even reaching a depth of 20 to 30 meters underground, which intersects with the groundwater level. At this time, when the traditional "enclosure structure + anchor rod (anchor cable)" support form is adopted, if the groundwater level is high during the construction of anchor rods or anchor cables, a large amount of groundwater will gush out during the drilling process, accompanied by a large amount of medium loss in the stratum, causing the enclosure structure to settle and deform significantly, thereby affecting the safety of surrounding structures and posing serious safety hazards.

[0005] In addition, during the construction process of water-rich sand layers, when drilling is carried out using casing follow-up construction, due to the poor cohesion of the sand layer, under the action of water pressure, after drilling to the designed depth, water and sand will gush out from the end of the casing, causing the casing to be blocked by sand and the anchor rods or cables to be unable to be installed smoothly.

[0006] Patent application 202311013585.6 discloses an underwater anchor cable construction method, which relates to the field of anchor cable construction technology, and includes the following steps: drilling and staking out; installing the first section casing and multiple sections of casing, and drilling; drilling to the depth of the first section casing exceeding the set hole depth; pulling out the anchor cable drill rod, retreating and injecting chemical slurry, and gradually forming a sealing body at the bottom of the hole, the first section casing and the multiple sections of casing; using an anchor cable drilling rig to drill holes, cleaning the sealing body in the multiple sections of casing, and stopping when drilling to the designed hole depth; lowering the anchor cable, free section anchor cable protective sleeve, isolation and centering bracket, primary grouting pipe and secondary grouting pipe; primary grouting to form an anchor cable grouting body; pulling out the multiple sections of casing section by section, and performing secondary grouting once each time a section of casing is pulled out; inserting a water-swelling wooden plug into the lower end of the hole opening of the ground-connected wall to seal it; sealing the hole opening to form a cavity grouting body behind the wall; and finishing the hole. However, the underwater anchor cable construction method disclosed in the patent application has the following defects: (1) the hole mouth cannot maintain pressure during grouting at the bottom of the hole and in the first section of the casing, and the slurry will fill the casing, making it difficult to implement subsequent steps normally; (2) the hole mouth is sealed with a water-swelling wooden plug, which makes construction difficult; (3) when removing the outer casing, there are no appropriate measures to control the sand gushing, which will cause the anchor rod and cable to be pulled out together with the outer casing.

[0007] Therefore, providing a construction method that is suitable for installation below the groundwater level and can successfully complete the installation of anchor rods and anchor cables has become an issue that urgently needs to be solved in the industry. Summary of the invention

[0008] In view of the above problems, one of the objects of the present invention is to provide a boot-type method for constructing anchor rods and cables below the groundwater level line, which realizes the smooth construction of anchor rods and cables below the groundwater level line by controlling sand gushing from the hole mouth, limiting the amount of sand discharged from the drilling hole, grouting at the bottom of the hole to reinforce the stratum and installing the boot, pressure-maintaining grouting to pull out the outer casing and pressure-maintaining grouting to seal the hole, thereby providing a new choice for the construction of anchor rods and cables below the water level line in the industry.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] The present invention provides a boot-type anchor rod and anchor cable construction method below the groundwater level line, which comprises the following steps:

[0011] (1) Making the anchor rod body or anchor cable body according to the predetermined length;

[0012] (2) Setting a hole position on the enclosure structure, and installing a hole opening anti-burst device at the hole opening of the hole position;

[0013] (3) Connecting the two ends of the pressure-maintaining, limiting, and grouting device to the outer casing and the power head of the drilling rig respectively, passing the inner drill rod through the inner cavity of the pressure-maintaining, limiting, and grouting device and connecting it to the power head of the drilling rig, and drilling through the hole mouth anti-burst device at the hole position. During the drilling process, the amount of sand discharged during the drilling process is controlled by adjusting the opening and closing state of the valve at the slag discharge hole of the pressure-maintaining, limiting, and grouting device until the hole is drilled to the designed depth to form an anchor hole;

[0014] (4) removing the pressure-maintaining, draining and grouting device, injecting bentonite slurry into the outer casing through the inner drill rod, and after the outer casing is filled with the bentonite slurry, connecting one end of the pressure-maintaining grouting device to the outer casing, connecting one end of the inner drill rod to the power head, passing the other end of the inner drill rod through the pressure-maintaining grouting device and extending it into the anchor hole, and performing a first grouting into the bottom area of ​​the outer casing located in the anchor hole through the inner drill rod to reinforce the bottom area and form a bottom reinforcement area;

[0015] (5) removing the pressure-maintaining grouting device, extending a steel pipe into the anchor hole until the bottom end of the outer sleeve, pouring bentonite slurry into the steel pipe to wash the hole, and after washing the hole, installing the boot to the bottom of the anchor hole and entering the bottom reinforcement area;

[0016] (6) extending the anchor rod body or the anchor cable body from the outer casing into the anchor hole until it is installed at the boot sleeve, and performing a second grouting into the outer casing through the primary grouting pipe of the anchor rod body or the anchor cable body until the bentonite slurry is completely replaced;

[0017] (7) Install the pressure-maintaining, drain-limiting and grouting device, connect the two ends of the pressure-maintaining, drain-limiting and grouting device to the outer casing and the power head of the drilling rig respectively, perform the third grouting from the air sleeve of the power head, and perform pressure-maintaining grouting on the inside of the outer casing. During the pressure-maintaining grouting process, completely close the valve at the slag discharge hole of the pressure-maintaining, drain-limiting and grouting device, start the power head, and drive the outer casing to rotate under the rotation of the power head, so that the outer casing is pulled out of the anchor hole;

[0018] (8) When the outer sleeve is pulled out to the outside of the enclosure structure, a fourth grouting is performed through the outer sleeve under pressure-maintaining conditions, and the outer sleeve is continuously pulled out to the hole opening to seal the hole opening, and then the outer sleeve is removed;

[0019] (9) 20 to 24 hours after the hole opening is sealed, performing secondary supplementary grouting on the anchoring section of the anchor body or anchor cable body through the secondary grouting pipe of the anchor body or anchor cable body; and

[0020] (10) 7 to 10 days after the completion of the secondary supplementary grouting, the anchor rod body or anchor cable body is tensioned and locked, and the hole is subjected to secondary closed grouting.

[0021] In some embodiments, in step (1), the anchor rod body or anchor cable body includes: a primary grouting steel flower pipe, 2 to 4 secondary grouting steel flower pipes, a bracket and a steel strand, wherein the bracket is provided with a central through hole at the center, 2 to 4 sub-holes are provided around the central through hole, and a plurality of semicircular grooves facing the center are provided at the outer edge of the bracket, the primary grouting steel flower pipe is passed through the central through hole, a secondary grouting steel flower pipe is passed through each of the sub-holes, a steel strand is accommodated in each groove, and the 2 to 4 secondary grouting steel flower pipes have different lengths.

[0022] In some embodiments, in step (1), the stent is made of steel or plastic.

[0023] In some embodiments, in step (2), the enclosure structure is a ground-connected wall or other structure.

[0024] In some embodiments, in step (2), before installing the orifice anti-bumping device, the periphery of the orifice of the hole is roughened and leveled.

[0025] In some embodiments, in step (3), the drilling method is air drilling, water drilling or mud wall drilling, and the outer casing follows the process.

[0026] In some embodiments, in step (3), the outer diameter of the outer casing is set to 60 mm to 200 mm, and the outer diameter of the inner drill rod is set to 50 mm to 114 mm.

[0027] Among them, in step (4), the bentonite slurry is injected (i.e., the first bentonite slurry is injected, before the bottom sealing grouting) to replace the mud and sand in the outer casing. Since the bentonite slurry has a certain viscosity and specific gravity, it can wrap the mud and sand in the middle outer casing and bring it out of the hole. Then, the pressure-maintaining grouting device is installed to make most of the inner part of the outer casing filled with bentonite slurry, so as to prevent the slurry from entering during the subsequent grouting and prevent the slurry from solidifying, so as to facilitate the removal of the inner drill rod.

[0028] In some embodiments, in step (4), the bottom reinforcement zone is set to a stratum 1 to 5 meters away from the bottom of the outer casing.

[0029] In some embodiments, the grouting material used in step (4) has the characteristics of anti-dispersion, fast setting, and high permeability.

[0030] In some embodiments, the grouting pressure of the first grouting is 0.5-1 MPa, and the slurry of the first grouting is composed of the following raw materials in parts by weight: 80-100 parts of water, 100 parts of cement and 180-200 parts of water glass.

[0031] In some embodiments, the length of the steel pipe used in step (5) is greater than the depth of the anchor hole.

[0032] In some embodiments, in step (5), the outer diameter of the steel pipe is set to 15 mm to 50 mm.

[0033] In some embodiments, in step (5), a grouting pipe is connected to the steel pipe, and bentonite slurry is injected through a grouting machine to wash the hole.

[0034] Among them, in step (5), bentonite slurry is injected (i.e., the second injection of bentonite slurry, after the bottom grouting). Since impurities such as sand still exist in the outer casing after the first injection of bentonite slurry, it is not completely filled with bentonite slurry. The second injection of bentonite slurry is after the bottom grouting is completed. At this time, the bottom of the outer casing has been grouting reinforced, and the bottom reinforcement area has been formed. The bottom of the outer casing will no longer have sand gushing phenomenon, which is equivalent to the bottom of the outer casing being in a closed state. At this time, injecting bentonite slurry again can replace all the sand in the outer casing, so that the outer casing is filled with bentonite slurry, thereby facilitating the subsequent installation of anchor rods / anchor cables.

[0035] In some embodiments, the bentonite slurry injected in step (4) and step (5) has the same components, both of which include the following components in parts by weight: 100 parts of water and 50 parts of bentonite, and both are grouting at normal pressure.

[0036] In some embodiments, in step (5), the boot cover includes a boot cover columnar body and a cone connected to the bottom of the boot cover columnar body, and the outer diameter of the boot cover is set to 60 mm to 200 mm, and the length is set to 50 cm to 200 cm.

[0037] In some embodiments, in step (5), the boot sleeve is made of a steel tube that is 5 to 10 mm smaller than the inner diameter of the outer sleeve.

[0038] In some embodiments, in step (6), the second grouting is normal pressure grouting, and the slurry of the second grouting is cement slurry, and the cement slurry is composed of the following raw materials in parts by weight: 45 parts of water, 100 parts of cement, and 1 part of water reducer, wherein the water reducer is one of lignin sulfonate water reducer, naphthalene water reducer, melamine water reducer, aminosulfonate water reducer, fatty acid water reducer or polycarboxylate water reducer.

[0039] In some embodiments, in step (6), the cement slurry is injected under normal pressure, and the water-cement ratio of the cement slurry is 0.4 to 0.55:1.

[0040] In some embodiments, in step (7), the grouting pressure of the third grouting is 0.2-0.5 MPa, and the slurry of the third grouting is cement slurry, which is composed of the following raw materials in parts by weight: 45 parts of water, 100 parts of cement and 1 part of water reducer, wherein the water reducer is one of lignin sulfonate water reducer, naphthalene water reducer, melamine water reducer, aminosulfonate water reducer, fatty acid water reducer or polycarboxylate water reducer.

[0041] In some embodiments, in step (7), the outer casing is subjected to pressure-maintaining grouting by means of the pressure-maintaining, drainage-limiting and grouting device, and the outer casing is pulled out while grouting.

[0042] Among them, in the process of pulling out the outer casing in step (7), due to the certain water head pressure during the construction of the underwater anchor rod body / anchor cable body, when the outer casing is pulled out, the medium in the formation (such as sand) will be affected by the water pressure and flow into the inner part of the outer casing, wrapping the anchor rod body / anchor cable body, causing the anchor rod body / anchor cable body to be pulled out together when the outer casing is pulled out. The pressure-maintaining grouting here is to maintain a certain pressure inside the outer casing so that the medium in the formation cannot enter the inner part of the casing.

[0043] Among them, the pressure-maintaining condition in step (8) refers to the situation in step (7) when the outer casing is just pulled out after pressure-maintaining grouting. When the outer casing is pulled out to the outside of the retaining structure, the injection of cement slurry is stopped. At this time, the inside of the outer casing is completely filled with cement slurry, and the medium in the formation cannot flow into the casing. At this time, the valves on the pressure-maintaining and grouting devices are in a closed state, and a certain pressure is maintained inside the outer casing.

[0044] In some embodiments, in step (8), the grouting pressure of the fourth grouting is 0.3-1.5 MPa, and the slurry of the fourth grouting is composed of the following raw materials in parts by weight: 45 parts of water, 100 parts of cement, 1 part of water reducer and 40-80 parts of water glass, wherein the water reducer is one of lignin sulfonate water reducer, naphthalene water reducer, melamine water reducer, aminosulfonate water reducer, fatty acid water reducer or polycarboxylate water reducer.

[0045] In some embodiments, in step (9), the grouting pressure of the secondary supplementary grouting is 0.5-1 MPa, and the slurry of the secondary supplementary grouting is cement slurry with a water-cement ratio of 0.4-0.55:1.

[0046] In some embodiments, in step (10), the grouting pressure of the closed grouting is 0.3-0.5 MPa, and the slurry of the closed grouting is composed of the following raw materials in parts by weight: 45 parts of water, 100 parts of cement, 1 part of water reducer and 40-80 parts of water glass, or polyurethane chemical pulp is used, wherein the water reducer is one of lignin sulfonate water reducer, naphthalene water reducer, melamine water reducer, aminosulfonate water reducer, fatty acid water reducer or polycarboxylate water reducer, and the polyurethane chemical pulp is oily polyurethane.

[0047] In some embodiments, in step (2), the orifice anti-bumping device includes: a fixing plate group, a sealing plate and a positioning plate group, wherein the fixing plate group includes a first end plate fixed to the enclosure structure, a first connecting plate connected to the top end of the first end plate and extending outward, a second connecting plate connected to the bottom end of the first end plate and extending outward, and a second end plate connected between the first connecting plate and the second connecting plate, the length of the first connecting plate is less than the length of the second connecting plate, the sealing plate is arranged on the outer surface of the second end plate, the positioning plate group is pressed at the outer edge of the sealing plate and fixed to the second end plate, a first through hole is opened in the center of the first end plate, a second through hole is opened in the center of the second end plate, and a central through hole is opened in the center of the sealing plate, so that the outer casing passes through the central through hole, the second through hole and the first through hole in sequence to enter the underground, and the angle between the first end plate and the second end plate is set to 15 to 25 degrees.

[0048] In some embodiments, a sealing gasket is sandwiched between the first end plate of the orifice anti-bumping device and the enclosure structure.

[0049] In some embodiments, the positioning plate group of the orifice anti-bumping device includes a plurality of pressure plate sheets, each of which is arranged around the outer edge of the sealing plate.

[0050] In some embodiments, the first end plate of the orifice burst prevention device is connected to the enclosure structure by expansion bolts.

[0051] In some embodiments, the diameter of the central through hole of the orifice anti-bumping device is smaller than the diameter of the outer sleeve, and the diameters of the first through hole and the second through hole are larger than the diameter of the outer sleeve.

[0052] In some embodiments, the first end plate and the second end plate of the orifice burst prevention device are both steel plates.

[0053] In some embodiments, the first end plate and the second end plate of the orifice anti-bumping device are provided with bolt holes.

[0054] In some embodiments, the sealing plate of the orifice anti-burst device is a rubber plate.

[0055] In some embodiments, the sealing gasket plate of the orifice anti-bumping device is a rubber plate or a polyurethane plate.

[0056] In some embodiments, in step (3), the pressure-maintaining, drainage-limiting and grouting device includes: a hollow casing, a first interface provided at one end of the hollow casing, a second interface provided at the other end of the hollow casing, and 2 to 3 slag discharge holes arranged in a ring on the outer wall of the hollow casing and connected to the inner cavity of the hollow casing, wherein the aperture of the first interface matches the aperture of the outer sleeve, the aperture of the second interface matches the power head, the aperture of the inner cavity of the hollow casing is larger than the aperture of the inner drill rod, and a valve is provided at the orifice of the slag discharge hole to control the opening and closing state of the corresponding slag discharge hole.

[0057] In some embodiments, the inner wall of the first interface of the pressure-maintaining and drainage-limiting and grouting device is provided with a first internal thread for threaded connection with the outer casing.

[0058] In some embodiments, the inner wall of the second interface of the pressure-maintaining and exhaust-limiting grouting device is provided with a second internal thread for threaded connection with the power head.

[0059] In some embodiments, the outer wall of the orifice of each slag discharge hole of the pressure-maintaining, drainage-limiting and grouting device is provided with an external thread for threaded connection with the valve.

[0060] In some embodiments, a ball valve or a butterfly valve is provided at the orifice of each slag discharge hole of the pressure-maintaining, drainage-limiting and grouting device.

[0061] In some embodiments, the diameters of the first interface and the second interface of the pressure-maintaining, drainage-limiting and grouting device are the same.

[0062] In some embodiments, the first interface and the second interface have different diameters.

[0063] In some embodiments, the diameters of the first interface and the second interface are adjusted according to the sizes of the outer casing and the drilling rig power head.

[0064] In some embodiments, in step (4), the pressure-maintaining grouting device includes: a hollow cavity, a casing port provided at one end of the hollow cavity, a first grouting end plate provided at the other end of the hollow cavity, a second grouting end plate bolted to the first grouting end plate, and a sealing chamber body clamped between the first grouting end plate and the second grouting end plate, wherein the inner wall of the casing port is provided with an internal thread for threaded connection with the outer casing, the first grouting end plate, the second grouting end plate and the sealing chamber body are provided with coaxial through holes, a sealing member is provided in the sealing chamber body, and the inner diameter of the sealing member matches the outer diameter of the inner drill rod.

[0065] In some embodiments, the outer diameter of the inner drill rod is 1 to 2 cm smaller than the diameter of the through hole of the sealed chamber.

[0066] In some embodiments, the diameter of the through hole of the first grouting end plate is 1 to 2 cm larger than the outer diameter of the inner drill rod.

[0067] In some embodiments, the seal is a V-type composite seal.

[0068] In some embodiments, the hollow cavity is integrally connected to the first end plate.

[0069] By adopting the above technical scheme, the present invention at least obtains the following technical effects: (1) when drilling, the water and sand gushing out of the casing is limited by the hole mouth anti-burst device; (2) when drilling, the opening and closing state of the valve at the slag discharge hole of the pressure-maintaining and limiting discharge and grouting device is adjusted to control the sand discharge during the drilling process, thereby realizing the operation of controlling the sand gushing out of the outer casing; (3) after grouting to reinforce the formation in the bottom area of ​​the hole, the sand gushing is limited by the boot sleeve to prevent the situation that the anchor rod and anchor cable are not installed in place; (4) by installing the pressure-maintaining and limiting discharge and grouting devices, the outer casing can be pulled out while grouting, thereby preventing the sand gushing out of the casing and preventing the anchor rod body (anchor cable body) from being pulled out together with the outer casing; (5) the hole mouth is sealed by the quick-setting slurry under the pressure-maintaining condition to prevent the sand gushing out of the hole mouth after the outer casing is completely pulled out. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 A schematic structural diagram of the bracket of the anchor cable body in step (1) of the present invention is shown;

[0071] Figure 2 A schematic diagram showing the state of step (2) of the present invention is shown;

[0072] Figure 3 A state diagram of step (3) of the present invention is shown;

[0073] Figure 4 A state diagram of step (4) of the present invention is shown;

[0074] Figure 5 A state diagram of step (5) of the present invention is shown;

[0075] Figure 6 A state diagram showing step (6) of the present invention is shown;

[0076] Figure 7A-7D A state diagram of step (7) of the present invention is shown;

[0077] Figure 8 A state diagram of step (8) of the present invention is shown;

[0078] Fig. 9 A state diagram of step (9) of the present invention is shown;

[0079] Fig.10 A state diagram of step (10) of the present invention is shown;

[0080] Fig.11 A side cross-sectional view of the orifice anti-burst device of the present invention is shown;

[0081] Fig.12 A front view of the orifice anti-burst device of the present invention is shown;

[0082] Fig.13 The schematic diagram of the structure of the pressure-maintaining, exhaust-limiting and grouting device of the present invention is shown;

[0083] Fig.14 A schematic diagram showing the use status of the pressure-maintaining, exhaust-limiting and grouting device of the present invention is shown;

[0084] Fig.15 The schematic structural diagram of the pressure-maintaining grouting device of the present invention is shown;

[0085] Fig.16 A schematic diagram showing the use state of the pressure-maintaining grouting device of the present invention is shown;

[0086] Fig.17 A schematic diagram of the structure of the boot cover of the present invention is shown;

[0087] Description of reference numerals:

[0088] 0-embedded hole, 1-enclosure structure, 2-drilling rig, 3-power head, 4-outer casing, 5-inner drill rod, 6-bottom reinforcement area, 7-mixing barrel, 8-grouting machine, 9-grouting pipe, 10-boot sleeve, 101-boot sleeve columnar body, 102-cone, 11-anchor cable body, 110-bracket, 1101-center through hole, 1102-sub-hole, 1103-groove, 12-wind sleeve, K-hole mouth anti-burst device, K1-fixed plate group, K2-sealing plate, K3-positioning plate group, K1-fixed plate group, K11-first end plate, K110-first through hole, K12-second end plate, K120-second through hole, KL1 -First connecting plate, KL2-second connecting plate, K2-sealing plate, K20-center through hole, K3-positioning plate group, K30-pressure plate, K4-sealing pad, X-pressure maintaining, limiting and grouting device, X1-hollow casing, X11-first interface, X110-first internal thread, X12-second interface, X120-second internal thread, X13-slag discharge hole, X130-valve, J-pressure maintaining and grouting device, J1-hollow cavity, J2-casing port, J21-internal thread, J3-first end plate, J4-second end plate, J5-sealing bin, J6-seal, Q-bolt, P-expansion bolt, S-underground. DETAILED DESCRIPTION

[0089] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are 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 making creative work are within the scope of protection of the present invention.

[0090] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc., are used to define components, only for the convenience of distinguishing the above components, and unless otherwise stated, the above terms have no special meanings and cannot be understood as indicating or implying relative importance.

[0091] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0092] Next, the boot-type anchor rod and anchor cable construction method below the groundwater level line of the present invention will be described in detail with reference to the accompanying drawings.

[0093] First, in step 1, an anchor rod body or an anchor cable body 11 is manufactured according to a predetermined length. In this non-limiting embodiment, the anchor cable body 11 includes: a primary grouting steel flower tube, three secondary grouting steel flower tubes, a bracket 110 and a steel strand, wherein Figure 1 As shown, a central through hole 1101, three sub-holes 1102 and six semicircular grooves 1103 are provided at the center of the bracket 110. A primary grouting steel flower tube is passed through the central through hole 1101, and a secondary grouting steel flower tube is passed through each sub-hole 1102. A steel strand is accommodated in each groove 1103, so that the anchor body 11 is fastened as a whole by using the bracket 110.

[0094] Then, in step 2, if Figure 2 As shown, the periphery of the embedded hole 0 of the anchor rod body or anchor cable body on the surface of the enclosure structure 1 is first roughened, and then the hole mouth anti-burst device K is installed, wherein the hole mouth anti-burst device K is firmly connected to the enclosure structure 1 by using expansion bolts.

[0095] Then, in step 3, if Figure 3 As shown, first, the two ends of the pressure-maintaining, limiting and grouting device X are connected to the power head 3 and the outer casing 4 of the drilling rig 2 respectively, the inner drill rod 5 passes through the inner cavity of the pressure-maintaining, limiting and grouting device X and is connected to the power head 3 of the drilling rig, and the hole is drilled through the hole mouth anti-burst device K at the hole position until the hole is drilled to the designed depth to form an anchor hole. During the drilling process, a pneumatic drill, a water drill or a mud wall protection process can be used to form a hole, and the opening and closing state of the valve at the slag discharge hole of the pressure-maintaining, limiting and grouting device X can be adjusted to control the sand discharge or slag discharge during the drilling process, and maintain the formation pressure so as not to affect the formation stability.

[0096] When the drilling reaches the designed depth, the outer casing 4 is separated from the pressure-maintaining and limiting drainage and grouting device X, and bentonite slurry is first injected into the outer casing 4 through the inner drill rod 5. After the outer casing 4 is filled with bentonite slurry, Figure 4As shown, one end of the pressure-maintaining grouting device J is connected to the outer casing 4, one end of the inner drill rod 5 is connected to the power head 3 of the drilling rig 2, the other end of the inner drill rod 5 passes through the pressure-maintaining grouting device J and extends into the anchor hole, and is connected to the grouting machine 8 through the grouting pipe 9, and the slurry stirred in the mixing barrel 7 is injected into the bottom area of ​​the outer casing through the grouting machine 8 and the inner drill rod 5 to reinforce the 1 to 5 meter stratum in the bottom area of ​​the hole to form a bottom reinforcement area 6. Among them, the grouting pressure is 0.8MPa, and the grouting liquid includes: 100 parts of water, 100 parts of cement and 180 parts of water glass.

[0097] Then, in step 5, if Figure 5 As shown, the pressure-maintaining grouting device J is removed, a steel pipe is inserted into the anchor hole until the bottom end of the outer sleeve 4, and bentonite slurry is poured into the steel pipe to wash the hole. After washing the hole, the pre-made boot cover 10 is installed to the bottom of the hole and enters the bottom reinforcement area 6. Fig.17 As shown, the boot cover 10 includes a boot cover columnar body 101 and a cone 102 connected to the bottom of the boot cover columnar body 101. The outer diameter of the boot cover 10 is set to 100 mm and the length is set to 200 cm.

[0098] Then, in step 6, if Figure 6 As shown, the pre-made anchor cable body 11 is installed in the outer casing 4, extending downward along the outer casing 4 until entering the boot sleeve 10, and the grouting machine 8 and the primary grouting pipe in the anchor cable body 11 are connected through the grouting pipe 9, and the slurry stirred in the mixing barrel 7 is poured into the outer casing 4 through the grouting machine 8 and the primary grouting hole of the anchor cable body 11 and filled. This grouting is normal pressure grouting, and the grouting liquid includes 45 parts of water, 100 parts of cement and 1 part of polycarboxylate water reducer.

[0099] Then, in step 7, if 7A to 7D As shown, the pressure-maintaining and drain-limiting and grouting device X is installed again, and the two ends of the pressure-maintaining and drain-limiting and grouting device X are respectively connected to the outer casing 4 and the power head 3 of the drilling rig, and the grouting machine 8 and the wind sleeve 12 of the power head 3 are connected through the grouting pipe 9. Grouting is performed from the wind sleeve 12, and the outer casing 4 is slowly pulled outwards while grouting until it is pulled out to the outside of the enclosure structure 1. The grouting pressure of this step of grouting is 0.3MPa, and the grouting liquid is a cement slurry including 45 parts of water, 100 parts of cement and 1 part of polycarboxylate-based water reducer.

[0100] Then, in step 8, if Figure 8 As shown, the grouting machine 8 and the pressure-maintaining and limiting drainage and grouting device X are connected through the grouting pipe 9, and the slurry stirred in the mixing barrel 7 is injected through the grouting machine 8, and a suitable amount of water glass is added to quickly seal the embedded hole 0, and the outer sleeve 4 is removed. In this step, the grouting pressure is 1MPa, and the grouting slurry includes: 45 parts of water, 100 parts of cement, 1 part of polycarboxylate water reducer and 60 parts of water glass.

[0101] Afterwards, in step 9, after the outer casing 4 is removed, the anchor cable body 11 is subjected to secondary supplementary grouting after the strength waiting time is not less than 24 hours.

[0102] Finally, in step 10, 7 to 10 days after the second supplementary grouting, the anchor cable body is tensioned and locked according to the designed tension value. If there is water leakage at the hole, the hole is sealed and grouted for the second time through the reserved grouting pipe. When tensioning, the designed tension value is adjusted according to different positions.

[0103] In this non-limiting embodiment, Fig.11 As shown, the hole mouth anti-burst device K in step 2 includes: a fixing plate group K1, a sealing plate K2 and a positioning plate group K3.

[0104] Specifically, the fixing plate group K1 includes: a first end plate K11, a second end plate K12, a first connecting plate KL1 and a second connecting plate KL2. The first end plate K11 is firmly connected to the enclosure structure 1 through expansion bolts P, the first connecting plate KL1 is welded to the top end of the first end plate K11 and extends outward, the second connecting plate KL2 is welded to the bottom end of the first end plate K11 and extends outward, and the second end plate K12 is welded between the first connecting plate KL1 and the second connecting plate KL2. Fig.11 As shown, the length of the first connecting plate KL1 is less than the length of the second connecting plate KL2, so that a certain angle is formed between the first end plate K11 and the second end plate K12, thereby achieving the effect of oblique insertion of the outer sleeve and oblique stretching of the anchor rod and anchor cable. In this non-limiting embodiment, the first connecting plate KL1 and the second connecting plate KL2 can be steel pipes or steel plates.

[0105] like Fig.11 and Fig.12 As shown, a sealing plate K2 made of a rubber plate is arranged on the outer surface of the second end plate K12, a positioning plate group K3 is pressed on the outer edge of the sealing plate K2, and is fixed to the second end plate K12 by bolts Q, a first through hole K110 is opened at the center of the first end plate K11, a second through hole K120 is opened at the center of the second end plate K12, and a central through hole K20 is opened at the center of the sealing plate K2, so that the outer sleeve 4 can pass through the central through hole K20, the second through hole 110 and the first through hole 120 in sequence to enter the underground S.

[0106] In this non-limiting embodiment, in order to prevent water and sand from gushing between the first end plate K11 and the enclosure structure 1 , a sealing pad K4 made of a rubber plate or a polyurethane plate is sandwiched between the first end plate K11 and the enclosure structure 1 .

[0107] In order to prevent underground mud and sand from gushing out from the outer wall of the outer casing, the diameter of the central through hole K20 of the present invention is smaller than the diameter of the outer casing 4, thereby utilizing the elasticity of the sealing plate itself so that the central through hole K20 can tightly clamp the outer wall of the outer casing 4.

[0108] As another non-limiting embodiment, Fig.12 The positioning plate group K3 includes a plurality of pressure plate pieces K30, each of which is arranged around the outer edge of the sealing plate K3 and then fixed to the second end plate K12 by bolts, thereby achieving a fixing effect of the sealing plate K3.

[0109] Therefore, when using the hole mouth anti-bumping device K, firstly, the first end plate K11 is firmly connected to the enclosure structure 1 by the expansion bolts P, and the first end plate K11 and the enclosure structure 1 are sealed by a sealing pad K4 made of a rubber plate or a polyurethane plate, and the second end plate K12 is inclined at an angle of 20 degrees to the first end plate through the first connecting plate KL1 and the second connecting plate KL2, and the central through hole K20 of the sealing plate K2 is aligned with the second through hole K120 of the second end plate K12, and then the outer sleeve 4 is successively passed through the central through hole K20, the second through hole K120 and the first through hole K110 to the underground S, and then each pressure plate K30 is pressed on the sealing plate K2 and fixed to the second end plate K12 by bolts Q, thereby completing the entire installation process.

[0110] In this non-limiting embodiment, Fig.13 As shown, the pressure-maintaining, limited-discharge and grouting device X used in step 3 includes: a hollow casing X1 with a hollow structure inside, the two ends of the hollow casing X1 are respectively a first interface X11 and a second interface X12, and two slag discharge holes 13 connected to the inner cavity of the hollow casing X1 are provided on the outer wall of the hollow casing X1.

[0111] During use, if Fig.14 As shown, the inner drill rod 5 can pass through the inner cavity of the hollow casing X1, the aperture of the first interface X11 matches the aperture of the outer casing 4, the inner wall of the first interface X11 is provided with a first internal thread X110, so that it can be threadedly connected to the outer casing 4, the aperture of the second interface X12 matches the power head 3, the inner wall of the second interface X12 is provided with a second internal thread X120, so that it can be threadedly connected to the power head 3, and a ball valve or a butterfly valve serving as a valve X130 is provided at the orifice of the slag discharge hole X13 to control the opening and closing state of the corresponding slag discharge hole.

[0112] Therefore, when drilling, the drilling rig is connected to the outer casing 4 through the first interface X11, and the inner drill rod 5 passes through the inside of the hollow casing X1. When using a pneumatic drill, a water drill or a mud wall to drill holes, the amount of slag discharge in the drilling is controlled by controlling the switch of the ball valve or butterfly valve at the orifice of the slag discharge hole X13 according to the slag discharge amount of the stratum, so as to achieve the purpose of controlling deformation. After the anchor rod or anchor cable is installed, when the outer casing 4 needs to be pulled out, the switch of the ball valve or butterfly valve at the orifice of the slag discharge hole X13 is completely closed, and then the grouting pump and the drilling rig power head 3 are connected through the grouting pipe. When the outer casing 4 is pulled out, the grouting pump injects cement slurry through the outer casing 4 to maintain pressure in the outer casing 4 to prevent the stratum medium from pouring into the outer casing 4, wrapping the outer casing 4 and the anchor cable body 11, and causing the anchor cable body 11 to be pulled out together with the outer casing 4.

[0113] As another non-limiting embodiment, the pressure-maintaining grouting device J used in step 4 is as follows: Fig.15 As shown, it includes: a hollow cavity J1, a first end plate J3, a second end plate J4 and a sealing chamber J5. Specifically, one end of the hollow cavity J1 is provided with a casing port J2, and the other end of the hollow cavity J1 is provided with an integrally connected first end plate J3, the second end plate J4 is connected to the first end plate J3 by a bolt Q, and the sealing chamber J5 is sandwiched between the first end plate J3 and the second end plate J4, wherein the first end plate J3, the second end plate J4 and the sealing chamber J5 are provided with coaxial through holes, and a sealing member J6 is provided in the sealing chamber J5. The aperture of the casing port J2 matches the aperture of the outer sleeve 4, the inner wall of the casing port J2 is provided with an internal thread J21, so that it can be threadedly connected with the outer sleeve 4, and the inner diameter of the sealing member J6 matches the outer diameter of the inner drill rod 5, thereby, the inner drill rod 5 can achieve a sealing effect by using the sealing member J6.

[0114] During use, before grouting the bottom, if Fig.16 As shown, the pressure-maintaining grouting device J is connected to the outer casing 4 through the casing port J2. Since the interior of the pressure-maintaining grouting device J is a hollow structure, the inner drill rod 5 passes through the second end plate J4, the sealing chamber J5, and the first end plate J3 in sequence, and passes through the interior of the hollow cavity J1. A V-shaped combined seal J6 is installed in the sealing chamber J5. The tightness of the V-shaped combined seal J6 is controlled by the bolts Q on the second end plate J4 and the first end plate J3 to seal the inner drill rod 5 tightly, and then grouting is performed to achieve the effect of maintaining pressure in the outer casing and preventing the slurry from flowing back into the outer casing.

[0115] In the underwater anchor construction of Yujingwan Community in Tongzhou District, Beijing, the boot-type anchor cable construction method provided by the present invention was used for test construction. During the test construction process, the problem of sand gushing in the pre-buried pipe and casing during the previous anchor cable construction below the water level line was successfully avoided, and the bottom sealing grouting was used to ensure the smooth installation of the anchor cable body. The casing was removed first under the pressure-maintaining grouting condition, which also avoided the anchor cable body from being pulled out. Specifically, the acceptance test data is shown in Table 1.

[0116] Table 1 Acceptance test data

[0117]

[0118] It can be seen from Table 1 that among the 6 anchor cables inspected for acceptance, the designed standard value of axial tension is 670KN. When loaded to 1.4 times the standard value of axial tension, the displacement of the anchor head is stable, and the measured elastic displacement is greater than 80% of the theoretical elastic elongation of the free section length, thus judging that the construction is qualified.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A boot-type anchor cable construction method below the groundwater level, characterized in that: The steps include: (1) Making the anchor rod body or anchor cable body according to the predetermined length; (2) Setting a hole position on the enclosure structure, and installing a hole opening anti-burst device at the hole opening of the hole position; (3) Connecting the two ends of the pressure-maintaining, limiting, and grouting device to the outer casing and the power head of the drilling rig respectively, passing the inner drill rod through the inner cavity of the pressure-maintaining, limiting, and grouting device and connecting it to the power head of the drilling rig, and drilling through the hole mouth anti-burst device at the hole position. During the drilling process, the amount of sand discharged during the drilling process is controlled by adjusting the opening and closing state of the valve at the slag discharge hole of the pressure-maintaining, limiting, and grouting device until the hole is drilled to the designed depth to form an anchor hole; (4) removing the pressure-maintaining, draining and grouting device, injecting bentonite slurry into the outer casing through the inner drill rod, and after the outer casing is filled with the bentonite slurry, connecting one end of the pressure-maintaining grouting device to the outer casing, connecting one end of the inner drill rod to the power head, passing the other end of the inner drill rod through the pressure-maintaining grouting device and extending it into the anchor hole, and performing a first grouting into the bottom area of ​​the outer casing located in the anchor hole through the inner drill rod to reinforce the bottom area and form a bottom reinforcement area; (5) removing the pressure-maintaining grouting device, extending a steel pipe into the anchor hole until the bottom end of the outer sleeve, pouring bentonite slurry into the steel pipe to wash the hole, and after washing the hole, installing the boot to the bottom of the anchor hole and entering the bottom reinforcement area; (6) extending the anchor rod body or the anchor cable body from the outer casing into the anchor hole until it is installed at the boot sleeve, and performing a second grouting into the outer casing through the primary grouting pipe of the anchor rod body or the anchor cable body until the bentonite slurry is completely replaced; (7) Install the pressure-maintaining, drain-limiting and grouting device, connect the two ends of the pressure-maintaining, drain-limiting and grouting device to the outer casing and the power head of the drilling rig respectively, perform the third grouting from the air sleeve of the power head, and perform pressure-maintaining grouting on the inside of the outer casing. During the pressure-maintaining grouting process, completely close the valve at the slag discharge hole of the pressure-maintaining, drain-limiting and grouting device, start the power head, and drive the outer casing to rotate under the rotation of the power head, so that the outer casing is pulled out of the anchor hole; (8) When the outer sleeve is pulled out to the outside of the enclosure structure, a fourth grouting is performed through the outer sleeve under pressure-maintaining conditions, and the outer sleeve is continuously pulled out to the hole opening to seal the hole opening, and then the outer sleeve is removed; (9) 20 to 24 hours after the hole opening is sealed, performing secondary supplementary grouting on the anchoring section of the anchor body or anchor cable body through the secondary grouting pipe of the anchor body or anchor cable body; and (10) 7 to 10 days after the completion of the secondary supplementary grouting, the anchor rod body or anchor cable body is tensioned and locked, and the hole is subjected to secondary closed grouting.

2. The method for constructing anchor rods and cables below the groundwater level according to claim 1, characterized in that: In step (1), the anchor rod body or anchor cable body includes: a primary grouting steel flower pipe, 2 to 4 secondary grouting steel flower pipes, a bracket and a steel strand, wherein the bracket is provided with a central through hole in the center, 2 to 4 sub-holes are provided around the central through hole, and a plurality of semicircular grooves facing the center are provided at the outer edge of the bracket, the primary grouting steel flower pipe is passed through the central through hole, a secondary grouting steel flower pipe is passed through each of the sub-holes, and a steel strand is accommodated in each groove, and the 2 to 4 secondary grouting steel flower pipes have different lengths.

3. The method for constructing anchor rods and cables below the groundwater level according to claim 1, characterized in that: In step (4), the bottom reinforcement area is set to a stratum 1 to 5 meters away from the bottom of the outer casing.

4. The method for constructing a boot-type anchor rod and cable below the groundwater level according to claim 1, characterized in that: In step (4), the grouting pressure of the first grouting is 0.5-1 MPa, and the slurry of the first grouting is composed of the following raw materials in parts by weight: 80-100 parts of water, 100 parts of cement and 180-200 parts of water glass.

5. The method for constructing anchor rods and cables below the groundwater level according to claim 1, characterized in that: In step (5), the boot cover includes a boot cover columnar body and a cone connected to the bottom of the boot cover columnar body. The outer diameter of the boot cover is set to 60 mm to 200 mm, and the length is set to 50 cm to 200 cm.

6. The method for constructing a boot-type anchor rod and cable below the groundwater level according to claim 1, characterized in that: In step (6), the second grouting is normal pressure grouting, and the slurry for the second grouting is cement slurry. The cement slurry is composed of the following raw materials in parts by weight: 45 parts of water, 100 parts of cement and 1 part of a water reducer, wherein the water reducer is one of a lignin sulfonate water reducer, a naphthalene water reducer, a melamine water reducer, an aminosulfonate water reducer, a fatty acid water reducer or a polycarboxylate water reducer.

7. The method for constructing a boot-type anchor rod and cable below the groundwater level according to claim 1, characterized in that: In step (7), the grouting pressure of the third grouting is 0.2-0.5 MPa, and the slurry of the third grouting is cement slurry, which is composed of the following raw materials in parts by weight: 45 parts of water, 100 parts of cement and 1 part of water reducer, wherein the water reducer is one of lignin sulfonate water reducer, naphthalene water reducer, melamine water reducer, aminosulfonate water reducer, fatty acid water reducer or polycarboxylate water reducer.

8. The method for constructing anchor rods and cables below the groundwater level according to claim 1, characterized in that: In step (8), the grouting pressure of the fourth grouting is 0.3-1.5 MPa, and the slurry of the fourth grouting is composed of the following raw materials in parts by weight: 45 parts of water, 100 parts of cement, 1 part of water reducer and 40-80 parts of water glass, wherein the water reducer is one of lignin sulfonate water reducer, naphthalene water reducer, melamine water reducer, aminosulfonate water reducer, fatty acid water reducer or polycarboxylate water reducer.

9. The boot-type anchor rod and cable construction method below the groundwater level according to claim 1, characterized in that: In step (9), the grouting pressure of the secondary supplementary grouting is 0.5-1 MPa, and the slurry of the secondary supplementary grouting is cement slurry with a water-cement ratio of 0.4-0.55:

1.

10. The method for constructing a boot-type anchor rod and cable below the groundwater level according to claim 1, characterized in that: In step (10), the grouting pressure of the closed grouting is 0.3-0.5 MPa, and the slurry of the closed grouting is composed of the following raw materials in parts by weight: 45 parts of water, 100 parts of cement, 1 part of water reducer and 40-80 parts of water glass, or polyurethane chemical pulp is used, wherein the water reducer is one of lignin sulfonate water reducer, naphthalene water reducer, melamine water reducer, aminosulfonate water reducer, fatty acid water reducer or polycarboxylate water reducer, and the polyurethane chemical pulp is oily polyurethane.

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