Foundation pit anchor cable and surface layer construction method

Abstract

The invention discloses a foundation pit anchor cable and surface layer construction method. Four inner walls of a foundation pit are defined by A, B, C and D respectively; face A construction, anchor cable construction and face layer construction; b face construction: when the first layer of anchor cables and the surface layer of the A face are constructed, earthwork of the first layer of anchor cables and the surface layer of the B face and earthwork of the bevel angle of the A face and the B face are synchronously excavated and transported; c-face construction: when the first layer of anchor cables and the surface layer of the B-face are constructed, excavating and transporting earthwork of the first layer of anchor cables and the surface layer of the C-face and earthwork of the bevel angle of the B-face and the C-face synchronously; d-face construction, when the first layer of anchor cables and the surface layer of the C-face are constructed, earthwork of the first layer of anchor cables and the surface layer of the D-face and earthwork of the oblique angle of the CD-face are excavated and transported synchronously; a foundation pit anchor cable and a surface layer are constructed face by face according to the sequence of A, B, C and D, earthwork of the next face is excavated synchronously during construction of each face, and synchronous implementation of gradual reinforcement of foundation pit supporting and earthwork excavation is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of engineering construction, and in particular to a foundation pit anchor cable and surface layer construction method. Background Art

[0002] The foundation pit is an earth pit excavated according to the design requirements of the underground structure. During the excavation process, the static equilibrium state of the underground soil around the foundation pit is broken, the internal pressure of the soil is automatically unloaded, and the soil pressure type is converted from static soil pressure to active soil pressure. In order to achieve a new equilibrium state, the side walls of the foundation pit are prone to move into the pit and even collapse. Therefore, slope and support treatment of the side walls of the foundation pit become necessary construction steps.

[0003] The traditional foundation pit construction method is usually to complete the foundation pit support pile and crown beam construction, and then start to excavate the earth from the top of the foundation pit until it reaches the bottom of the foundation pit. Then, the anchor cable and surface layer construction are carried out from the bottom to the top, and the anchor cable tensioning is completed at the same time. However, this construction method has some obvious defects:

[0004] Firstly, the inner wall of the excavated foundation pit cannot be processed in time during the excavation process, which poses a great safety hazard in the entire foundation pit construction process. The inner wall of the foundation pit is exposed to the outside for a long time and is easily affected by environmental factors such as rain erosion and temperature changes, which may cause the soil structure to loosen or partially collapse.

[0005] Secondly, this top-down excavation method makes the support construction period of the entire foundation pit longer. Since it is necessary to wait until the foundation pit is completely excavated before starting the anchor cable and surface layer construction, this serial operation method greatly prolongs the entire construction period and affects the progress of the project.

[0006] In addition, traditional methods also make it difficult to optimize the construction process and efficiently utilize resources. For example, it is impossible to support other excavated areas while excavating a certain area. This inflexible construction sequence may lead to idle equipment and human resources, reducing overall construction efficiency.

[0007] Finally, the traditional method also has shortcomings in ensuring the stability of the foundation pit. Since the excavation surface cannot be supported in time, it may cause uneven stress release of the soil, increasing the risk of foundation pit deformation and surrounding ground subsidence.

[0008] Therefore, in order to solve the above problems, it is necessary to provide a foundation pit anchor cable and surface layer construction method. Summary of the invention

[0009] In view of this, the purpose of the present invention is to provide a foundation pit anchor cable and surface layer construction method, to improve the anchor cable and surface layer construction efficiency, reduce the risk of foundation pit insecurity, and at the same time cross-construction with earthwork to reduce the entire foundation pit support work cycle and save construction costs.

[0010] The foundation pit anchor cable and surface layer construction method provided by the present invention adopts the following technical scheme:

[0011] A foundation pit anchor cable and surface layer construction method comprises the following steps:

[0012] S1. The four inner walls of the foundation pit are defined as A, B, C, and D respectively;

[0013] S2, A surface construction;

[0014] S21. Excavate the A surface to 0.8-1.2m below the first anchor cable layer, install steel mesh inside the piles, and set surface thickness control measures on the installed steel mesh on the A surface before spraying the surface concrete;

[0015] S22, spray the surface concrete according to the set thickness control points, keep the nozzle vertical to the sprayed surface, and wait until the surface concrete strength reaches the anchor hole making condition, then carry out anchor cable construction, and use special machinery to drill holes;

[0016] S24. After the steel strand extrusion anchor is crimped, the steel strands are arranged around the drill pipe through the non-resistance guiding device, and the anchor plate and the positioning bracket are installed simultaneously to lock the steel strands;

[0017] S25, performing anchor cable grouting, during which the anchor cable is pushed in, the drill rod is rotated alternately forward and reversely to perform grouting, and an anchor cable positioning bracket is synchronously set when adding the drill rod;

[0018] S26, after the anchor cable reaches the predetermined position, the drill rod starts to retreat, and at the same time, the grout is sprayed by rotating alternately forward and reverse. When the nozzle reaches the free section of the anchor cable, the grout is stopped, and the drill rod withdraws from the anchor hole;

[0019] S27, complete the construction of the first layer of anchor cables and the surface layer of the A surface in sequence and install the waist beam, and complete the tensioning of the anchor cables while installing the waist beam;

[0020] S3, B surface construction: while the first layer of anchor cables and surface layer of A surface are being constructed, the earthwork in the construction area of ​​the first layer of anchor cables and surface layer of B surface and the earthwork at the angle of A and B surfaces are being excavated and transported simultaneously. When the first layer of anchor cables and surface layer of A surface is completed, the first layer of anchor cables and surface layer of B surface can be constructed. The construction method of anchor cables and surface layer of B surface is the same as that of anchor cables and surface layer of A surface.

[0021] S4, C surface construction: while the first layer of anchor cables and surface layer of B surface are being constructed, the earthwork in the construction area of ​​the first layer of anchor cables and surface layer of C surface and the earthwork at the angle of B and C surfaces are being excavated and transported simultaneously. When the first layer of anchor cables and surface layer of B surface are constructed, the first layer of anchor cables and surface layer of C surface can be constructed. The construction method of anchor cables and surface layer of C surface is the same as that of A surface.

[0022] S5, D surface construction: while the first layer of anchor cables and surface layer of C surface are being constructed, the earthwork in the construction area of ​​the first layer of anchor cables and surface layer of D surface and the earthwork at the oblique angle of CD surface are being excavated and transported simultaneously. When the first layer of anchor cables and surface layer of C surface are constructed, the first layer of anchor cables and surface layer of D surface can be constructed. The construction method of anchor cables and surface layer of D surface is the same as that of A surface.

[0023] S6, construction of the next layer of surface A: while the first layer of anchor cables and surface layer of surface D are being constructed, the earthwork in the construction area of ​​the second layer of anchor cables and surface layer of surface A and the first layer of earthwork at the angle of surface D and A are being excavated and transported simultaneously. When the first layer of anchor cables and surface layer of surface D are constructed, the second layer of anchor cables and surface layer of surface A can be constructed;

[0024] S7. Construction of the next layer B, C, D surface: The construction methods of the anchor cables and surface layers of the subsequent second, third, fourth, etc. layers are the same.

[0025] Furthermore, in step S22, when spraying the surface concrete, the spraying at about 1000 mm below the anchor cable is controlled to be an inclined surface inclined toward the soil layer.

[0026] Furthermore, the guiding device includes a support frame and a roller arranged on the support frame, and the anchor cable moves into the anchor hole through the roller on the support frame.

[0027] Furthermore, a guide frame for mounting rollers is provided on the support frame, the guide frame is arranged in a circular shape, the rollers are evenly arranged inside the guide frame, and the anchor cable passes through the guide frame and contacts the rollers.

[0028] Furthermore, the guide frame includes a fixed frame fixed on the support frame and a movable frame arranged on the fixed frame, one side of the fixed frame and the movable frame are hinged and buckled together to form a circular guide frame, and a lock for fixing the movable frame is arranged on one side of the fixed frame and the movable frame that can be opened and closed.

[0029] Furthermore, a handle is provided on one side of the movable frame that can be opened and closed.

[0030] Furthermore, reinforcing steel bars are arranged in a crisscross pattern around the anchor cables on the steel mesh.

[0031] Furthermore, the positioning bracket is arranged in a ring shape, the steel strands are evenly arranged on the circumference of the positioning bracket, and the drill rod passes through the positioning bracket.

[0032] Furthermore, a plurality of mounting portions for mounting the steel strands are evenly arranged on the circumference of the positioning bracket, and one side of the mounting portion can be opened and closed for placing the steel strands therein.

[0033] Furthermore, one side of the positioning bracket can be opened and closed to allow the drill rod to pass through.

[0034] In summary, the present invention has at least one of the following beneficial effects: the foundation pit anchor cables and surface layers are constructed face by face in the order of A, B, C, and D, and the earthwork of the next face is excavated simultaneously during the construction of each face, thereby realizing the gradual reinforcement of the foundation pit support and the simultaneous excavation of earthwork, and effectively solving the safety hazards, long construction period, low resource utilization efficiency, and poor foundation pit stability existing in the traditional construction methods, and having the advantages of improving construction safety, shortening the construction period, optimizing resource utilization, and enhancing the stability of the foundation pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of four sides of the foundation pit according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the anchor cable and surface layer layers according to an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the construction of the first floor of an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the construction of the second floor according to an embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram of a surface steel mesh according to an embodiment of the present invention;

[0040] Figure 6 A schematic diagram of a slope reserved at the lower end of the surface layer in an embodiment of the present invention;

[0041] Figure 7 This is a schematic diagram of a drill rod passing through a positioning bracket according to an embodiment of the present invention;

[0042] Figure 8 This is a schematic diagram of a steel strand guiding device according to an embodiment of the present invention;

[0043] Fig. 9 It is a schematic diagram of anchor cable construction according to an embodiment of the present invention.

[0044] Description of reference numerals:

[0045] 1. Steel mesh; 11. Reinforcement steel bars; 2. Guide device; 21. Support frame; 22. Roller; 23. Guide frame; 231. Fixed frame; 232. Movable frame; 233. Lock; 234. Handle; 3. Positioning bracket; 31. Installation part; 4. Surface layer; 5. Anchor cable; 6. Waist beam. DETAILED DESCRIPTION

[0046] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0047] The following is combined with Figure 1-9 The present invention is described in further detail.

[0048] The embodiment of the present invention discloses a foundation pit anchor cable and surface layer construction method. Figure 1-Figure 9 The foundation pit anchor cable and surface layer construction method includes the following steps:

[0049] S1. The four inner walls of the foundation pit are defined as A, B, C, and D respectively;

[0050] S2, A surface construction;

[0051] S21. Excavate the A surface to 0.8-1.2m below the first anchor cable 5, preferably install the steel mesh 1 inside the 1m pile row, and set the surface layer 4 thickness control measures on the installed steel mesh 1 on the A surface before spraying the surface layer 44 concrete;

[0052] S22, spraying the surface layer 4 concrete according to the set thickness control point, keeping the nozzle vertical to the sprayed surface, and wait until the surface layer 4 concrete strength reaches the anchor cable 5 hole making condition, and then construct the anchor cable 5, and use special machinery to drill holes;

[0053] S24, after the steel strand extrusion anchor crimping is completed, the steel strands are respectively arranged around the drill pipe through the non-resistance guiding device 2, and the anchor plate and the positioning bracket 3 are simultaneously installed and the steel strands are locked;

[0054] S25, grouting the anchor cable 5, pushing the anchor cable 5 in during the grouting process, rotating the drill rod alternately forward and reverse to perform a grouting, and synchronously setting the anchor cable 5 positioning bracket 3 when adding the drill rod;

[0055] S26, after the anchor cable 5 reaches the predetermined position, the drill rod starts to retreat, and at the same time, the grout is sprayed by rotating alternately forward and reverse. When the nozzle reaches the free section of the anchor cable 5, the grout is stopped, and the drill rod withdraws from the anchor hole;

[0056] S27, sequentially complete the construction of the anchor cable 5 and the surface layer 4 of the A surface and install the waist beam 6, and complete the tensioning of the anchor cable 5 while installing the waist beam 6;

[0057] S3, B surface construction: while the first layer of anchor cables 5 and surface layer 4 of the A surface are being constructed, the earthwork in the construction area of ​​the first layer of anchor cables 5 and surface layer 4 of the B surface and the earthwork at the oblique angle of the A and B surfaces are excavated and transported simultaneously. When the first layer of anchor cables 5 and surface layer 4 of the A surface are constructed, the first layer of anchor cables 5 and surface layer 4 of the B surface can be constructed. The steel mesh 1 and concrete at the intersection of the A and B surfaces are overlapped and compacted. The construction method of the anchor cables 5 and surface layer 4 of the B surface is the same as that of the anchor cables 5 and surface layer 4 of the A surface.

[0058] S4, C surface construction: while the first layer of anchor cable 5 and surface layer 4 of B surface are being constructed, the earthwork in the construction area of ​​the first layer of anchor cable 5 and surface layer 4 of C surface and the earthwork at the oblique angle of B and C surfaces are excavated and transported simultaneously. When the first layer of anchor cable 5 and surface layer 4 of B surface are constructed, the first layer of anchor cable 5 and surface layer 4 of C surface can be constructed. The steel mesh 1 and concrete at the intersection of B and C surfaces are overlapped and compacted. The construction method of anchor cable 5 and surface layer 4 of C surface is the same as that of A surface.

[0059] S5, D surface construction: while the first layer of anchor cable 5 and surface layer 4 are being constructed on the C surface, the earthwork in the construction area of ​​the first layer of anchor cable 5 and surface layer 4 on the D surface and the earthwork at the oblique angle of the CD surface are excavated and transported simultaneously. When the first layer of anchor cable 5 and surface layer 4 on the C surface are completed, the first layer of anchor cable 5 and surface layer 4 on the D surface can be constructed. The steel mesh 1 and concrete at the intersection of the C and D surfaces are overlapped and compacted. The construction method of the anchor cable 5 and surface layer 4 on the D surface is the same as that on the A surface.

[0060] S6, construction of the next layer of surface A: while the first layer of anchor cables 5 and surface layer 4 of surface D are being constructed, the earthwork in the construction area of ​​the second layer of anchor cables 5 and surface layer 4 of surface A and the earthwork of the first layer at the oblique angle of surface D and A are excavated and transported simultaneously. When the first layer of anchor cables 5 and surface layer 4 of surface D are constructed, the second layer of anchor cables 5 and surface layer 4 of surface A can be constructed. The steel mesh 1 and concrete at the intersection of surface D and A and the first and second layers are overlapped and compacted;

[0061] S7. Construction of the next layer B, C, D surface: The construction method of the anchor cable 5 and surface layer 4 of the subsequent second, third, fourth, etc. layers is the same.

[0062] By defining the four inner walls of the foundation pit as A, B, C, and D, and constructing them one by one, the problem of not being able to timely process the inner walls of the excavated foundation pit during the excavation of the foundation pit is solved. Specifically, the excavation of the A surface is about 1000mm below the first layer of anchor cable 5, and the steel mesh 1 is installed inside the pile. Before spraying the surface layer 4 concrete, the surface layer 4 thickness control measures are set on the steel mesh 1 installed on the A surface. Spray the surface layer 4 concrete according to the set thickness control point, keep the nozzle vertical to the sprayed surface, and wait until the strength of the surface layer 4 concrete reaches the anchor cable 5 hole making condition to carry out the anchor cable 5 construction, and use special machinery to drill holes. After the steel strand extrusion anchor is crimped, the steel strand is set around the drill rod through the resistance-free guide device 2, and the anchor plate and positioning bracket 3 are installed simultaneously and the steel strand is locked. Grouting of the anchor cable 5 is carried out, and the anchor cable 5 is pushed in during the grouting process. The drill rod rotates forward and reverse alternately to spray once, and the anchor cable 5 positioning bracket 3 is set synchronously when the drill rod is added. After the anchor cable 5 reaches the predetermined position, the drill rod begins to retreat, while rotating forward and reverse alternately to spray grout. When the nozzle reaches the free section of the anchor cable 5, the spraying stops, and the drill rod exits the anchor hole. The construction of the anchor cable 5 and the surface layer 4 on the A side is completed in sequence, and the waist beam 6 is installed. The anchor cable 5 is tensioned while the waist beam 6 is installed. Through these steps, the stability of the inner wall of the foundation pit can be effectively guaranteed, the risk of collapse can be reduced, the construction safety can be improved, and the construction period can be shortened.

[0063] In this embodiment, in step S22, when spraying the surface layer 4 concrete, the spraying control is about 1000mm below the anchor cable 5 as an inclined surface inclined inwardly toward the soil layer, so that it forms an inclined surface inclined inwardly toward the soil layer. In this way, it can ensure that the concrete below the anchor cable 5 can fit the soil layer more closely, thereby providing a better support effect and avoiding loosening and displacement of the soil layer; when spraying concrete, a specific spraying device can be used to control the spraying angle and direction to ensure the formation of the required inclined surface. The spraying device can include an adjustable nozzle and an angle control device. The nozzle adjusts the angle and spraying pressure to form an inwardly inclined surface below the anchor cable 5. The spraying device can be equipped with a laser rangefinder or other positioning device to ensure the accuracy of the spraying position. In addition, a layered spraying method can be used during the spraying process to construct an inwardly inclined surface layer by layer to ensure the uniformity and stability of the concrete layer. By controlling the spraying direction, the concrete below the anchor cable 5 can fit the soil layer more closely, providing a better support effect, reducing the risk of loosening and displacement of the soil layer, and significantly improving the safety and stability of the foundation pit construction.

[0064] In this embodiment, the guiding device 2 includes a support frame 21 and a roller 22 arranged on the support frame 21. The anchor cable 5 is moved into the anchor hole by the roller 22 on the support frame 21. The guiding device 2 reduces the friction and resistance of the anchor cable 5 during movement through the cooperation of the support frame 21 and the roller 22, thereby improving the efficiency and accuracy of the construction of the anchor cable 5. The anchor cable 5 can move into the anchor hole more smoothly and without resistance, which effectively solves the problems of low efficiency and inaccurate positioning of the anchor cable 5 due to friction and resistance during the construction process.

[0065] In this embodiment, a guide frame 23 for installing rollers 22 is provided on the support frame 21. The guide frame 23 is arranged in a circular shape. The rollers 22 are evenly arranged on the inner side of the guide frame 23. The anchor cable 5 passes through the guide frame 23 and contacts the rollers 22, so that the anchor cable 5 can contact the rollers 22 when passing through the guide frame 23, thereby reducing the friction of the anchor cable 5 when moving, and improving the installation efficiency and accuracy of the anchor cable 5.

[0066] In this embodiment, the guide frame 23 includes a fixed frame 231 fixed on the support frame 21 and a movable frame 232 arranged on the fixed frame 231. One side of the fixed frame 231 and the movable frame 232 are hinged and buckled together to form a circular guide frame 23. The fixed frame 231 and the movable frame 232 are provided with a lock 233 that fixes the movable frame 232 on one side that can be opened and closed. The fixed frame 231 and the movable frame 232 are hinged and buckled together on one side to form an integral circular guide frame 23. The hinged design allows the movable frame 232 to rotate around the hinge point to achieve opening and closing. The other side is fixed by setting the lock 233 to fix the movable frame 232, so that the guide frame 23 can be stably maintained in a closed state when in use. The lock 233 can be used. Various forms, such as spring locks, bolt locks, etc., are used to ensure that the movable frame 232 can be firmly fixed when closed. In addition, the materials of the movable frame 232 and the fixed frame 231 can be made of high-strength metal materials to ensure that they can withstand greater forces during construction. The design of the guide frame 23 allows for quick and convenient installation and disassembly during construction, especially during the construction of the foundation pit anchor cable 5 and the surface layer 4. The opening and closing function of the guide frame 23 allows construction personnel to easily place the anchor cable 5 into the guide frame 23 and move it to the anchor hole through the roller 22, thereby improving construction efficiency. At the same time, the stability and firmness of the guide frame 23 also ensure the accurate positioning of the anchor cable 5 during construction, reducing errors and safety hazards that may occur during construction.

[0067] In this embodiment, a handle 234 is provided on the openable side of the movable frame 232. The handle 234 can be provided on the side or top of the movable frame 232 and installed by screw fixing or welding. The material of the handle 234 can be selected from metal or high-strength plastic to ensure its durability and reliability. By providing the handle 234, the operator can save effort and convenience when opening and closing the movable frame 232, avoiding the difficulties and inconveniences that may occur during manual opening and closing.

[0068] In this embodiment, the reinforcing steel bars 11 are crisscrossedly arranged around the anchor cable 5 on the steel mesh 1. The reinforcing steel bars 11 can be arranged in different ways. For example, the reinforcing steel bars 11 can be staggered at a certain interval and angle to ensure that a stable mesh structure is formed around the anchor cable 5. The reinforcing steel bars 11 can be made of high-strength steel to further improve its bearing capacity and tensile strength. In addition, the arrangement of the reinforcing steel bars 11 can be adjusted according to the specific conditions of the foundation pit. For example, in areas where the side walls of the foundation pit are weak, the density of the reinforcing steel bars 11 can be increased to provide a stronger support effect.

[0069] In this embodiment, the positioning bracket 3 is arranged in an annular shape, the steel strands are evenly arranged on the circumference of the positioning bracket 3, and the drill rod passes through the positioning bracket 3. The annular design of the positioning bracket 3 can be achieved by different materials and structures. For example, the positioning bracket 3 can be made of steel or alloy materials to provide sufficient strength and durability. The annular part of the positioning bracket 3 can be manufactured by an integrated molding process, or spliced ​​by multiple arc segments, which can be convenient for transportation and installation. The uniform arrangement of the steel strands can be achieved by setting a plurality of fixing holes or clamping devices on the circumference of the positioning bracket 3. These fixing holes or clamping devices can be adjustable to accommodate steel strands of different diameters and quantities; the positioning bracket 3 is arranged in an annular shape to ensure that the steel strands are evenly distributed on the circumference of the bracket during installation, so as to avoid the steel strands from being offset during the drilling process. The drill rod passes through the positioning bracket 3 to ensure stability and accuracy during the drilling process. The annular positioning bracket 3 and the evenly arranged steel strands solve the problem of inaccurate positioning of the anchor cable 5 in the construction of the foundation pit side wall support, and ensure the stability and safety of the anchor cable 5 construction.

[0070] In this embodiment, a plurality of mounting portions 31 for mounting the steel strands are evenly arranged on the circumference of the positioning bracket 3. One side of the mounting portion 31 can be opened and closed for placing the steel strands therein. This design can be achieved through hinges and locks. One side of the mounting portion can be connected to the positioning bracket 3 through a hinge, and a lock is provided on the other side. When the steel strand needs to be installed, the lock can be opened to open the mounting portion 31. After the steel strand is placed in, the lock can be closed to fix the steel strand in the mounting portion 31. The lock can be a spring lock or a spiral lock to ensure that the mounting portion can firmly fix the steel strand when closed, thereby achieving effective installation and fixation of the steel strand, thereby solving the problem of installation and fixation of the steel strand on the positioning bracket 3.

[0071] In this embodiment, one side of the positioning bracket 3 can be opened and closed to allow the drill rod to pass through. This openable and closable positioning bracket 3 can be achieved in a variety of ways. For example, a hinge structure can be used to enable one side of the positioning bracket 3 to be opened and closed like a door; a sliding structure can also be used to enable one side of the positioning bracket 3 to be slid open and closed. In addition, in order to ensure the stability and firmness of the positioning bracket 3 during the opening and closing process, a locking device such as a snap buckle or a buckle can be provided at the opening and closing part of the positioning bracket 3, which can ensure that the positioning bracket 3 is easy to operate during use and can firmly and reliably fix the drill rod.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A foundation pit anchor cable and surface layer construction method, characterized in that: The following steps are involved: S1. The four inner walls of the foundation pit are defined as A, B, C, and D respectively; S2, A surface construction; S21. Excavate the A surface to 0.8-1.2m below the first anchor cable layer, install steel mesh inside the piles, and set surface thickness control measures on the installed steel mesh on the A surface before spraying the surface concrete; S22, spray the surface concrete according to the set thickness control points, keep the nozzle vertical to the sprayed surface, and wait until the surface concrete strength reaches the anchor hole making condition, then carry out anchor cable construction, and use special machinery to drill holes; S24. After the steel strand extrusion anchor is crimped, the steel strands are arranged around the drill pipe through the non-resistance guiding device, and the anchor plate and the positioning bracket are installed simultaneously to lock the steel strands; S25, performing anchor cable grouting, during which the anchor cable is pushed in, the drill rod is rotated alternately forward and reversely to perform grouting, and an anchor cable positioning bracket is synchronously set when adding the drill rod; S26, after the anchor cable reaches the predetermined position, the drill rod starts to retreat, and at the same time, the grout is sprayed by rotating alternately forward and reverse. When the nozzle reaches the free section of the anchor cable, the grout is stopped, and the drill rod withdraws from the anchor hole; S27, complete the construction of the first layer of anchor cables and the surface layer of the A surface in sequence and install the waist beam, and complete the tensioning of the anchor cables while installing the waist beam; S3, B surface construction: while the first layer of anchor cables and surface layer of A surface are being constructed, the earthwork in the construction area of ​​the first layer of anchor cables and surface layer of B surface and the earthwork at the angle of A and B surfaces are being excavated and transported simultaneously. When the first layer of anchor cables and surface layer of A surface is completed, the first layer of anchor cables and surface layer of B surface can be constructed. The construction method of anchor cables and surface layer of B surface is the same as that of anchor cables and surface layer of A surface. S4, C surface construction: while the first layer of anchor cables and surface layer of B surface are being constructed, the earthwork in the construction area of ​​the first layer of anchor cables and surface layer of C surface and the earthwork at the angle of B and C surfaces are being excavated and transported simultaneously. When the first layer of anchor cables and surface layer of B surface are constructed, the first layer of anchor cables and surface layer of C surface can be constructed. The construction method of anchor cables and surface layer of C surface is the same as that of A surface. S5, D surface construction: while the first layer of anchor cables and surface layer of C surface are being constructed, the earthwork in the construction area of ​​the first layer of anchor cables and surface layer of D surface and the earthwork at the oblique angle of CD surface are being excavated and transported simultaneously. When the first layer of anchor cables and surface layer of C surface are constructed, the first layer of anchor cables and surface layer of D surface can be constructed. The construction method of anchor cables and surface layer of D surface is the same as that of A surface. S6, construction of the next layer of surface A: while the first layer of anchor cables and surface layer of surface D are being constructed, the earthwork in the construction area of ​​the second layer of anchor cables and surface layer of surface A and the first layer of earthwork at the angle of surface D and A are being excavated and transported simultaneously. When the first layer of anchor cables and surface layer of surface D are constructed, the second layer of anchor cables and surface layer of surface A can be constructed; S7. Construction of the next layer B, C, D surface: The construction methods of the anchor cables and surface layers of the subsequent second, third, fourth, etc. layers are the same.

2. The method for construction of foundation pit anchor cables and surface layers according to claim 1, characterized in that: In step S22, when spraying the surface concrete, the spraying at 1000 mm below the anchor cable is controlled to be an inclined surface inclined toward the soil layer.

3. The foundation pit anchor cable and surface layer construction method according to claim 1 is characterized in that: The guiding device comprises a supporting frame and a roller arranged on the supporting frame, and the anchor cable moves into the anchor hole through the roller on the supporting frame.

4. The method for construction of foundation pit anchor cables and surface layers according to claim 3 is characterized in that: A guide frame for mounting rollers is arranged on the support frame, the guide frame is arranged in a circular shape, the rollers are evenly arranged inside the guide frame, and the anchor cable passes through the guide frame and contacts the rollers.

5. The method for construction of foundation pit anchor cables and surface layers according to claim 4, characterized in that: The guide frame includes a fixed frame fixed on the support frame and a movable frame arranged on the fixed frame. One side of the fixed frame and the movable frame are hinged and buckled together to form a circular guide frame. The openable and closable side of the fixed frame and the movable frame is provided with a lock to fix the movable frame.

6. The foundation pit anchor cable and surface layer construction method according to claim 5 is characterized in that: A handle is provided on one side of the movable frame that can be opened and closed.

7. The foundation pit anchor cable and surface layer construction method according to claim 1 is characterized in that: The steel mesh is provided with reinforcing steel bars arranged in a crisscross pattern around the anchor cables.

8. The foundation pit anchor cable and surface layer construction method according to claim 1 is characterized in that: The positioning bracket is arranged in a ring shape, the steel strands are evenly arranged on the circumference of the positioning bracket, and the drill rod passes through the positioning bracket.

9. The foundation pit anchor cable and surface layer construction method according to claim 8, characterized in that: A plurality of mounting parts for mounting the steel strands are evenly arranged on the circumference of the positioning bracket, and one side of the mounting part can be opened and closed for placing the steel strands therein.

10. The method for construction of foundation pit anchor cables and surface layers according to claim 9, characterized in that: One side of the positioning bracket can be opened and closed for allowing the drill rod to pass through.

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