Construction method of prestressed anti-floating anchor rod based on digital simulation

Abstract

The application relates to a prestressed anti-floating anchor rod construction method based on digital simulation, and belongs to the anchor rod construction technical field, which comprises the following steps: a drilling machine is moved to an anchor rod position by a machine operator, and erection is completed; a hole position is rechecked by a surveyor, and the next step is entered after no error is found; the drilling machine is started to form a hole, and drilling is performed to a design depth; an anchor cable is placed, and the free section of the anchor cable is well treated for corrosion prevention and isolation; a secondary grouting method is adopted, a grouting pipe end is 150 mm away from a hole bottom, during grouting, a pipe opening is always buried in mortar, after the mortar is filled, the hole opening is blocked, grouting is supplemented at a pressure of 0.4-0.6 MPa, and pressure stabilization is performed for 10 minutes; when the strength of an anchor body and a condition test block reaches 80% of the design strength, prestress tensioning can be performed, the prestress value is generally 75%-80% of the design anchoring force, grading loading is performed, when the prestress of the anchor cable does not obviously attenuate, the anchor rod can be locked; when obvious stress loss occurs after locking, compensation tensioning should be performed. The anti-floating capacity of building engineering is improved.

Description

Technical Field

[0001] This invention relates to the field of anchor bolt construction technology, and specifically to a prestressed anti-buoyancy anchor bolt construction method based on digital simulation. Background Technology

[0002] Rock bolts are a fundamental component of roadway support in modern coal mines, reinforcing the surrounding rock and enabling it to support itself. Rock bolts are used not only in mines but also in engineering projects for the main reinforcement of slopes, tunnels, and dams. Rock bolts are a structural member system for reinforcing soil and rock masses; through the longitudinal tensile force of the bolt body, they overcome the disadvantage that the tensile strength of soil and rock is far lower than its compressive strength; essentially, the rock bolt, located within the soil and rock mass, forms a new composite with it. However, existing anti-buoyancy rock bolts in construction projects are unstable. The problem and defect of existing technology is the instability of existing anti-buoyancy rock bolts in construction projects. Summary of the Invention

[0003] This invention primarily addresses the shortcomings of existing anti-buoyancy anchor structures, which suffer from poor structural stability. It provides a prestressed anti-buoyancy anchor construction method based on digital simulation, employing a graded loading method. When the prestress in the anchor cable shows no significant attenuation, the anchor can be locked. If significant stress loss occurs after locking, compensatory tensioning should be performed. This improves the anti-buoyancy capability of building structures.

[0004] The above-mentioned technical problems of the present invention are mainly solved by the following technical solutions:

[0005] A prestressed anti-buoyancy anchor bolt construction method based on digital simulation includes the following steps:

[0006] Step 1: Construct a finite element model of the building's anti-buoyancy anchor bolts using model building software; then, scale down the original building structure and the existing foundation treatment method to create a simulation model.

[0007] Step two: Test the prestress of the anti-floating anchor rod using prestress testing equipment.

[0008] Step 3: Construct a visual 3D model of the anti-buoyancy anchor bolt construction using 3D software. Simulate the construction process based on the simulation model and the 3D model using BIM technology. Carry out the construction according to the simulation plan. The drilling rig is moved to the anchor bolt position by the operator and the installation is completed. The surveyor checks the hole position a second time. After confirming that there are no errors, proceed to the next step.

[0009] Step 4: Start the drilling rig to drill to the designed depth; install the anchor cable, and perform anti-corrosion and isolation treatment on the free section of the anchor cable; adopt the secondary grouting method, with the end of the grouting pipe 150mm away from the bottom of the hole. During grouting, the pipe opening should always be buried in the mortar. After the grout is filled, seal the hole opening and add grout at a pressure of 0.4-0.6MPa, and stabilize the pressure for 10 minutes.

[0010] Step 5: Once the strength of the anchor body test block reaches 80% of the design strength, prestressing can be carried out. The prestress value is generally 75% to 80% of the design anchoring force. The load is applied in stages. When there is no significant attenuation of the anchor cable prestress, the anchor rod can be locked. If there is significant stress loss after locking, compensatory tensioning should be carried out.

[0011] Preferably, the anchor bolts are installed after the concrete cushion layer of the underground structure's base slab is completed.

[0012] As a preferred option, a seepage test should be conducted on the borehole wall around the borehole during construction; the seepage rate around the borehole in the anchoring section should be greater than 0.01m. 3 When the flow rate is 1 / min, consolidation grouting or other methods should be used for filling.

[0013] As a preferred method, the drilling and cleaning methods for anti-buoyancy anchors are as follows:

[0014] 1) The position of the anchor bolts should be checked before the drilling rig is in place. The drilling rig should be positioned accurately, horizontally, vertically and stably.

[0015] 2) The allowable deviation of drilling verticality should be less than 1%, and the allowable deviation of hole position should be ±50mm.

[0016] Casing drilling is recommended for construction in unstable formations.

[0017] After the reinforcement is inserted into the hole and before grouting, debris inside the hole should be removed, and any hole collapse or deformation of the hole wall should be addressed.

[0018] As a preferred method, the fabrication, storage, and installation of anti-buoyancy anchor reinforcements are as follows:

[0019] (1) Ribs, support plates, nuts and other components should be prepared according to the design requirements, and the ribs should have a central structure attached;

[0020] (2) During the assembly, storage and transportation of the ribs, rust, damage, dirt or oil stains and excessive deformation should be prevented.

[0021] (3) The grouting pipe is inserted into the borehole along with the reinforcement, and the reinforcement extends out of the bottom of the pit by no less than 1.2 times the designed anchorage length;

[0022] (4) The reinforcement should be fixed at the opening and should not be shaken, pulled or collided before the grout reaches 70% of the design strength.

[0023] As a preferred method, the anchor bolt grout preparation and grouting method are as follows:

[0024] The sand diameter for mortar should not exceed 2mm, the mixing time should not be less than 1 minute, and it should be used immediately after mixing.

[0025] The grouting pump should be tested before use, and the pipe joints should be securely connected and sealed.

[0026] The grouting pipe should be inserted into the bottom of the hole and then pulled up 50mm to 100mm before grouting begins. Grouting should be carried out continuously.

[0027] For the first grouting, grout should overflow from the orifice. The second grouting should be carried out 4 to 8 hours after the first grouting. When the grouting pressure reaches 1.5 MPa or above, it should be stabilized for 5 minutes. If there are dewatering measures, measures should be taken to avoid pumping water from affecting the grouting quality.

[0028] As a preferred method, the tensioning and locking method for prestressed anchor bolts is as follows:

[0029] Before tensioning the anchor bolts, the tensioning equipment should be calibrated and set, and the bearing surface of the anchor head platform should be flat.

[0030] The compressive strength values ​​of the grout and the concrete base during tensioning should conform to the specifications in the table.

[0031]

[0032] Before the anchor bolt is formally tensioned, it is advisable to pre-tension the anchor bolt once or twice using 10% to 15% of the design tension value;

[0033] When the locking load of a load-distributed anchor bolt is equal to the design value of the pull-out force, it is advisable to use a parallel jack group to tension and lock each unit simultaneously; when the locking load is less than the design value of the pull-out force, each unit can be tensioned and locked sequentially from the bottom to the top of the borehole, and the force should be equal.

[0034] Tensioning should be uniform and orderly to avoid the adverse effects of concentrated tensioning in local areas on adjacent anchors. During the tensioning process, it is forbidden to disturb the reinforcement, jacks or other anchor clamps.

[0035] Completely record the tensioning load and deformation, and seal the anchor head promptly after tensioning is completed.

[0036] As a preferred method, the waterproofing and corrosion protection methods during anchor bolt construction are as follows:

[0037] The selected materials should comply with the relevant provisions and design requirements of the "Technical Specification for Waterproofing of Underground Engineering" GB50108, and modified bitumen paste, modified bitumen waterproof membrane and hot melt connection are recommended.

[0038] If groundwater seepage is discovered after cleaning the trench, measures should be taken to stop the water and ensure that there is no standing water around the anchor bolts.

[0039] The anchor body at the end of the anchor rod should be chiseled down to a dense area. After removing the loose dust or mud from the reinforcement, it should be leveled with polymer cement waterproof mortar to the top elevation required by the design.

[0040] Waterproofing should be applied according to design requirements. After hot-melting modified bitumen and other materials, they should be poured into the groove, leveled, and the waterproof membrane should be hot-melted and bonded in a timely manner.

[0041] The length of the anchor bar coating should not be less than 60mm, and the joint should be sealed with modified bitumen using hot melt.

[0042] As a preferred method, the following methods should be used to protect the finished anti-buoyancy anchor bolts:

[0043] Apply plain cement slurry to the reinforcing bars extending from the working surface to prevent them from being disturbed during the construction of the underground structure's base slab.

[0044] Before pouring concrete, the reinforcing steel should be inspected and subjected to secondary anti-corrosion treatment.

[0045] The construction method for anti-buoyancy treatment of existing works during the construction process is as follows:

[0046] Anchor bolt construction plans for structures with complex geological conditions and surrounding environment, and those sensitive to construction disturbance, should be specially demonstrated.

[0047] Prestressed members should be tensioned in stages;

[0048] Construction should not damage existing structures and components, and existing structures and components should be monitored.

[0049] As a preferred approach, the simulation method is as follows:

[0050] Preliminary data collection includes geographical information of the anti-buoyancy anchor construction site, three-dimensional dimensions of the anchor and the building, and anti-buoyancy anchor construction plan; the geographical information of the anti-buoyancy anchor construction site includes the plane coordinates and elevation point coordinates of the anti-buoyancy anchor construction site, and the anti-buoyancy anchor construction plan includes the anti-buoyancy anchor construction time, the division of the anti-buoyancy anchor construction area, the arrangement of anti-buoyancy anchor construction machinery, and the anti-buoyancy anchor construction tasks;

[0051] Based on the collected data, an anti-buoyancy anchor construction sub-model was established on the BIM platform, including an anti-buoyancy anchor construction site sub-model, an anchor model, and an anti-buoyancy anchor construction machinery sub-model. The anti-buoyancy anchor construction sub-model was generated using different modeling software. Specifically, the anti-buoyancy anchor construction site sub-model was generated using Civil3D software, the anchor model was established using Revit software, and the anti-buoyancy anchor construction machinery sub-model was created using Inventor software.

[0052] Information on the construction process of the anti-buoyancy anchor bolts is obtained from the anti-buoyancy anchor bolt construction scheme. The construction sub-model data and construction process information of the anti-buoyancy anchor bolts are then imported into the anti-buoyancy anchor bolt construction simulation platform to assemble the anti-buoyancy anchor bolt construction model. The anti-buoyancy anchor bolt construction simulation platform is the Navisworks platform. First, the construction sub-model data of each anti-buoyancy anchor bolt is converted into IFC standard format data, and the construction process information of the anti-buoyancy anchor bolts is created and stored in Microsoft Project as a non-IFC standard format. Then, the above data information is imported into the Navisworks platform, and the anti-buoyancy anchor bolt construction model is assembled on Navisworks.

[0053] An anti-buoyancy anchor construction simulation animation was created based on the anti-buoyancy anchor construction model. The creation process of the anti-buoyancy anchor construction simulation animation includes the association and matching of anti-buoyancy anchor construction progress information with the anti-buoyancy anchor construction model, the animation design of the operation of anti-buoyancy anchor construction machinery, and the rendering of the anti-buoyancy anchor construction scene.

[0054] The association and matching of the anti-buoyancy anchor construction progress information and the anti-buoyancy anchor construction model refers to simulating the anti-buoyancy anchor construction progress at different time intervals and establishing a specific correspondence between the anti-buoyancy anchor construction time arrangement and the anti-buoyancy anchor construction process. The method for establishing this is as follows: a specific paving schedule is created through Microsoft Project. This schedule is refined to each paving unit of each layer. That is, each paving unit establishes its own corresponding anti-buoyancy anchor construction task, which is associated with the action and time of the anti-buoyancy anchor construction machinery. Then, the anti-buoyancy anchor construction progress data is imported into the Timeliner module in Navisworks.

[0055] The animation design for the operation of the anti-buoyancy anchor bolt construction machinery includes the working animation of the anti-buoyancy anchor bolt construction machinery and the overall scheduling of the anti-buoyancy anchor bolt construction vehicles. The working animation of the anti-buoyancy anchor bolt construction machinery is obtained by the Animation module through capturing the machinery and simulating it using running commands. The scheduling of the anti-buoyancy anchor bolt construction vehicles is obtained by the Animation module through overall scheduling simulation of the anti-buoyancy anchor bolt construction machinery and vehicles. The rendering method for the anti-buoyancy anchor bolt construction scene is as follows: during post-processing, the animation of the anti-buoyancy anchor bolt construction machinery is added to the Timeliner, and the Presenter module is used to render the anti-buoyancy anchor bolt construction scene.

[0056] The present invention can achieve the following effects:

[0057] This invention provides a prestressed anti-buoyancy anchor bolt construction method based on digital simulation. Compared with existing technologies, this method involves: a machine operator moving the drilling rig to the anchor bolt position and setting it up; a surveyor performing a second check on the hole position, and proceeding to the next step after verification; starting the drilling rig to drill to the designed depth; placing the anchor cable, with the free section of the anchor cable treated for corrosion prevention and isolation; using a secondary grouting method, with the grouting pipe end 150mm from the bottom of the hole, ensuring the pipe opening is always submerged in mortar during grouting; sealing the hole opening after the grout is full, and then applying grout at a pressure of 0.4–0.6 MPa for 10 minutes; once the strength of the anchor body test block reaches 80% of the design strength, prestressing can be performed, with the prestress value generally being 75%–80% of the design anchoring force, applied in stages; and locking the anchor bolt when there is no significant attenuation of the anchor cable prestress. If there is significant stress loss after locking, compensating tensioning should be performed. This method can significantly improve the anti-buoyancy capability of building projects. Attached Figure Description

[0058] Figure 1 This is a flowchart of the prestressed anti-buoyancy anchor construction method of the present invention.

[0059] Figure 2 This is a flowchart of the drilling and cleaning method for the anti-buoyancy anchor bolt of the present invention.

[0060] Figure 3 This is a flowchart of the method for manufacturing, storing and installing the anti-buoyancy anchor reinforcement of the present invention. Detailed Implementation

[0061] The technical solution of the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0062] Example: Figure 1 As shown, the present invention provides a prestressed anti-buoyancy anchor bolt construction method based on digital simulation, comprising the following steps:

[0063] S101, construct a finite element model of the building's anti-buoyancy anchor bolt using model building software; and create a simulation model of the original building structure and existing foundation treatment method by scaling it down to a certain scale.

[0064] S102, testing the prestress of the anti-floating anchor rod using prestress testing equipment;

[0065] S103: A visual 3D model of the anti-buoyancy anchor bolt construction is built using 3D software. The construction process is simulated based on the simulation model and the 3D model using BIM technology. Construction is carried out according to the simulation plan. The drilling rig is moved to the anchor bolt position by the machine operator and the installation is completed. The surveyor conducts a second check on the hole position. After confirming that there are no errors, the next step is carried out.

[0066] S104, start the drilling rig to form a hole to the designed depth; install the anchor cable, and perform anti-corrosion and isolation treatment on the free section of the anchor cable; adopt the secondary grouting method, with the end of the grouting pipe 150mm away from the bottom of the hole. During grouting, the pipe opening should always be buried in the mortar. After the grout is filled, seal the hole opening and add grout at a pressure of 0.4-0.6MPa, and stabilize the pressure for 10 minutes.

[0067] S105, when the strength of the anchor body test block under the same conditions reaches 80% of the design strength, prestressing can be carried out. The prestress value is generally 75% to 80% of the design anchoring force. The load is applied in stages. When there is no significant attenuation of the anchor cable prestress, the anchor rod can be locked. If there is significant stress loss after locking, compensatory tensioning should be carried out.

[0068] The anchor bolts provided by this invention are best installed after the concrete cushion layer of the underground structure's base slab has been completed.

[0069] During construction, the method provided by this invention requires conducting a water seepage test on the borehole wall around the borehole; the water seepage rate around the borehole in the anchoring section should be greater than 0.01m. 3 When the flow rate is 1 / min, consolidation grouting or other methods should be used for filling.

[0070] like Figure 2 As shown, the drilling and cleaning method for anti-buoyancy anchors provided by this invention is as follows:

[0071] S201. Before the drilling rig is in place, the position of the anchor bolts should be checked. The drilling rig should be positioned accurately, horizontally, vertically and stably.

[0072] S202, the allowable deviation of drilling verticality should be less than 1%, and the allowable deviation of hole position should be ±50mm;

[0073] Casing drilling is recommended for construction in unstable formations.

[0074] After the reinforcement is inserted into the hole and before grouting, debris inside the hole should be removed, and any hole collapse or deformation of the hole wall should be addressed.

[0075] like Figure 3 As shown, the method for fabricating, storing, and installing anti-buoyancy anchor reinforcement provided by the present invention is as follows:

[0076] S301, Ribs, support plates, nuts and other components shall be prepared in accordance with design requirements, and the ribs shall have a centering structure attached to them;

[0077] S302. During the assembly, storage, and handling of the ribs, rust, damage, dirt or oil stains, and excessive deformation should be prevented.

[0078] S303, the grouting pipe is placed into the borehole together with the reinforcement, and the reinforcement extends out of the bottom of the foundation pit by no less than 1.2 times the designed anchorage length;

[0079] S304, the reinforcing bars should be fixed at the orifice and should not be shaken, pulled or collided before the grout reaches 70% of the design strength.

[0080] The anchor bolt grout preparation and grouting method provided by this invention are as follows:

[0081] The sand diameter for mortar should not exceed 2mm, the mixing time should not be less than 1 minute, and it should be used immediately after mixing.

[0082] The grouting pump should be tested before use, and the pipe joints should be securely connected and sealed.

[0083] The grouting pipe should be inserted into the bottom of the hole and then pulled up 50mm to 100mm before grouting begins. Grouting should be carried out continuously.

[0084] For the first grouting, grout should overflow from the orifice. The second grouting should be carried out 4 to 8 hours after the first grouting. When the grouting pressure reaches 1.5 MPa or above, it should be stabilized for 5 minutes. If there are dewatering measures, measures should be taken to avoid pumping water from affecting the grouting quality.

[0085] The prestressed anchor tensioning and locking method provided by this invention is as follows:

[0086] Before tensioning the anchor bolts, the tensioning equipment should be calibrated and set, and the bearing surface of the anchor head platform should be flat.

[0087] The compressive strength values ​​of the grout and the concrete base during tensioning should conform to the specifications in the table.

[0088] Before the anchor bolt is formally tensioned, it is advisable to pre-tension the anchor bolt once or twice using 10% to 15% of the design tension value;

[0089] When the locking load of a load-distributed anchor bolt is equal to the design value of the pull-out force, it is advisable to use a parallel jack group to tension and lock each unit simultaneously; when the locking load is less than the design value of the pull-out force, each unit can be tensioned and locked sequentially from the bottom to the top of the borehole, and the force should be equal.

[0090] Tensioning should be uniform and orderly to avoid the adverse effects of concentrated tensioning in local areas on adjacent anchors. During the tensioning process, it is forbidden to disturb the reinforcement, jacks or other anchor clamps.

[0091] Completely record the tensioning load and deformation, and seal the anchor head promptly after tensioning is completed.

[0092] The waterproofing and corrosion protection construction method for anchor bolts provided by this invention is as follows:

[0093] The selected materials should comply with the relevant provisions and design requirements of the "Technical Specification for Waterproofing of Underground Engineering" GB50108, and modified bitumen paste, modified bitumen waterproof membrane and hot melt connection are recommended.

[0094] If groundwater seepage is discovered after cleaning the trench, measures should be taken to stop the water and ensure that there is no standing water around the anchor bolts.

[0095] The anchor body at the end of the anchor rod should be chiseled down to a dense area. After removing the loose dust or mud from the reinforcement, it should be leveled with polymer cement waterproof mortar to the top elevation required by the design.

[0096] Waterproofing should be applied according to design requirements. After hot-melting modified bitumen and other materials, they should be poured into the groove, leveled, and the waterproof membrane should be hot-melted and bonded in a timely manner.

[0097] The length of the anchor bar coating should not be less than 60mm, and the joint should be sealed with modified bitumen using hot melt.

[0098] The method for protecting finished anti-buoyancy anchor bolts provided by this invention is as follows:

[0099] Apply plain cement slurry to the reinforcing bars extending from the working surface to prevent them from being disturbed during the construction of the underground structure's base slab.

[0100] Before pouring concrete, the reinforcing steel should be inspected and subjected to secondary anti-corrosion treatment.

[0101] The construction method for anti-buoyancy treatment of existing engineering projects provided by this invention is as follows:

[0102] Anchor bolt construction plans for structures with complex geological conditions and surrounding environment, and those sensitive to construction disturbance, should be specially demonstrated.

[0103] Prestressed members should be tensioned in stages;

[0104] Construction should not damage existing structures and components, and existing structures and components should be monitored.

[0105] The simulation method provided by this invention is as follows:

[0106] Preliminary data collection includes geographical information of the anti-buoyancy anchor construction site, three-dimensional dimensions of the anchor and the building, and anti-buoyancy anchor construction plan; the geographical information of the anti-buoyancy anchor construction site includes the plane coordinates and elevation point coordinates of the anti-buoyancy anchor construction site, and the anti-buoyancy anchor construction plan includes the anti-buoyancy anchor construction time, the division of the anti-buoyancy anchor construction area, the arrangement of anti-buoyancy anchor construction machinery, and the anti-buoyancy anchor construction tasks;

[0107] Based on the collected data, an anti-buoyancy anchor construction sub-model was established on the BIM platform, including an anti-buoyancy anchor construction site sub-model, an anchor model, and an anti-buoyancy anchor construction machinery sub-model. The anti-buoyancy anchor construction sub-model was generated using different modeling software. Specifically, the anti-buoyancy anchor construction site sub-model was generated using Civil3D software, the anchor model was established using Revit software, and the anti-buoyancy anchor construction machinery sub-model was created using Inventor software.

[0108] Information on the construction process of the anti-buoyancy anchor bolts is obtained from the anti-buoyancy anchor bolt construction scheme. The construction sub-model data and construction process information of the anti-buoyancy anchor bolts are then imported into the anti-buoyancy anchor bolt construction simulation platform to assemble the anti-buoyancy anchor bolt construction model. The anti-buoyancy anchor bolt construction simulation platform is the Navisworks platform. First, the construction sub-model data of each anti-buoyancy anchor bolt is converted into IFC standard format data, and the construction process information of the anti-buoyancy anchor bolts is created and stored in Microsoft Project as a non-IFC standard format. Then, the above data information is imported into the Navisworks platform, and the anti-buoyancy anchor bolt construction model is assembled on Navisworks.

[0109] An anti-buoyancy anchor construction simulation animation was created based on the anti-buoyancy anchor construction model. The creation process of the anti-buoyancy anchor construction simulation animation includes the association and matching of anti-buoyancy anchor construction progress information with the anti-buoyancy anchor construction model, the animation design of the operation of anti-buoyancy anchor construction machinery, and the rendering of the anti-buoyancy anchor construction scene.

[0110] The association and matching of the anti-buoyancy anchor construction progress information and the anti-buoyancy anchor construction model refers to simulating the anti-buoyancy anchor construction progress at different time intervals and establishing a specific correspondence between the anti-buoyancy anchor construction time arrangement and the anti-buoyancy anchor construction process. The method for establishing this is as follows: a specific paving schedule is created through Microsoft Project. This schedule is refined to each paving unit of each layer. That is, each paving unit establishes its own corresponding anti-buoyancy anchor construction task, which is associated with the action and time of the anti-buoyancy anchor construction machinery. Then, the anti-buoyancy anchor construction progress data is imported into the Timeliner module in Navisworks.

[0111] The animation design for the operation of the anti-buoyancy anchor bolt construction machinery includes the working animation of the anti-buoyancy anchor bolt construction machinery and the overall scheduling of the anti-buoyancy anchor bolt construction vehicles. The working animation of the anti-buoyancy anchor bolt construction machinery is obtained by the Animation module through capturing the machinery and simulating it using running commands. The scheduling of the anti-buoyancy anchor bolt construction vehicles is obtained by the Animation module through overall scheduling simulation of the anti-buoyancy anchor bolt construction machinery and vehicles. The rendering method for the anti-buoyancy anchor bolt construction scene is as follows: during post-processing, the animation of the anti-buoyancy anchor bolt construction machinery is added to the Timeliner, and the Presenter module is used to render the anti-buoyancy anchor bolt construction scene.

[0112] Application Examples: To demonstrate the inventiveness and technical value of the technical solution of the present invention, this section provides application examples of the technical solution of the claims on specific products or related technologies.

[0113] 1. Anchor Bolt Method

[0114] 1.1 Before construction, the material, specifications, and mechanical properties of reinforcing bars, steel strands, welding materials, anchor heads, grouting materials, etc., should be inspected. Before the reinforcement is installed, the integrity of the protective layer should be checked, and any damaged areas should be repaired.

[0115] 1.2 During construction, the location, borehole diameter and depth, reinforcement insertion length, grouting mix ratio, pressure and grouting volume records should be checked.

[0116] 1.3 The testing of anti-buoyancy anchor bolts should be carried out after the grout has reached the required curing period. The tested anti-buoyancy anchor bolts should meet the following requirements:

[0117] 1) Before construction, the records of rebar tying and concrete pouring should be checked;

[0118] 2) Before testing, the floating slurry on the reinforcement should be removed, and the end face of the slurry should be flat;

[0119] 3) After the existing structure is opened, it should be ensured that the reinforcement is not connected to the concrete.

[0120] 1.4 The testing of grouting anchor length and grout density shall be carried out in accordance with the current national standard "Technical Specification for Non-destructive Testing of Anchor Bolt Anchorage Quality" JGJ / T182. The sampling rate shall not be less than 10% of the total number of anchor bolts and each batch shall not be less than 20 bolts.

[0121] 1.5 No less than 10% of the tensioned anchor rods should be randomly selected for over-tensioning inspection, and the tension force should not be less than 1.2 times the design value.

[0122] 1.6 The quality inspection and acceptance standards for anti-buoyancy anchor bolts shall comply with the provisions of Table 1.6.

[0123]

[0124]

[0125] 2. Acceptance

[0126] 2.1 Acceptance of anti-buoyancy works shall be carried out after the construction unit has passed its self-inspection.

[0127] 2.2 In addition to complying with the current national standard "Standard for Acceptance of Construction Quality of Building Foundation Engineering" GB50202, the acceptance of anti-buoyancy engineering shall also meet the following requirements:

[0128] 1) Acceptance should be conducted separately for key control items and general items;

[0129] 2) Key controlled items must meet the acceptance standards. Any problems found should be dealt with immediately until the requirements are met.

[0130] 3) After the sub-projects have passed acceptance, the quality of the backfill soil in the fertilizer trench shall be witnessed and inspected.

[0131] 4) Waterproofing acceptance shall be carried out in accordance with the current national standards "Technical Specification for Waterproofing of Underground Engineering" GB50108 and "Code for Acceptance of Quality of Underground Waterproofing Engineering" GB50208.

[0132] 2.3 The acceptance of anti-buoyancy engineering projects should include the following technical documents and records:

[0133] 1) Survey and design documents, and product qualification certificates for raw materials and semi-finished products such as precast piles and steel cages;

[0134] 2) Component construction records and concealed works inspection and acceptance records;

[0135] 3) Performance test reports, including test reports on grout strength, concrete strength, and concrete-rock bond strength;

[0136] 4) Design change reports and documents detailing the handling of major issues;

[0137] 5) Supervision plan, implementation and supervision records, and supervision evaluation report;

[0138] 6) Monitoring plan, implementation, monitoring records, and monitoring result reports;

[0139] 7) Testing and witness sampling documents;

[0140] 8) Existing projects should also include verification exploration data and buoyancy safety assessment.

[0141] 9) Construction records and as-built drawings, and other required documents or records.

[0142] 3. Monitoring and Maintenance

[0143] 3.1 The monitoring plan shall be prepared in accordance with the anti-buoyancy engineering design documents and construction organization design documents, and shall include the entire process of construction and use. The monitoring plan shall include monitoring items, layout and quantity of measuring points, monitoring instruments and facilities, monitoring frequency, data processing and feedback, monitoring control standards and early warning values, and emergency response measures.

[0144] 3.2 When the monitoring requirements are not clearly specified in the anti-buoyancy engineering design documents, the monitoring items should be selected according to Table 3.2.

[0145] Table 3.2 Engineering Buoyancy Monitoring Items

[0146]

[0147] 3.3 Monitoring instruments should have good stability and long-term working performance. They should be calibrated before use and can only be used after passing the calibration.

[0148] 3.4 The groundwater level observation wells for anti-buoyancy projects shall comply with the provisions of the current industry standard "Code for Dynamic Observation of Urban Groundwater" CJJ76.

[0149] 3.5 Stress monitoring should be performed on anti-buoyancy structures and components, and the following requirements should be met:

[0150] 1) The number of monitoring points for the same type of component should not be less than 3;

[0151] 2) Monitoring points should be set up at different heights, and the number of points at the same elevation should not be less than 3;

[0152] 3) It is advisable to use two or more different monitoring methods for comparison and verification.

[0153] 3.6 When the following situations and the early warning situations in Table 3.6 occur during the monitoring of anti-buoyancy engineering,

[0154] Appropriate emergency response measures should be taken.

[0155] 1) Cracks appear in the components, and existing cracks develop further;

[0156] 2) Signs of sudden stress increase, relaxation, or pull-out appear in important components;

[0157] 3) Based on engineering experience, other situations may arise that require enhanced monitoring and handling.

[0158] Table 3.6 Early Warning Values ​​and Emergency Response Measures for Safety Control of Anti-buoyancy Engineering

[0159]

[0160] 3.7 Maintenance of anti-buoyancy works shall include both the construction and service phases, and shall comply with the following provisions:

[0161] 1) A regular inspection and maintenance system should be established to regularly check the project monitoring and inspection results and assess the project's safety status;

[0162] 2) It is advisable to have a regular inspection system and a routine testing plan for the designed service life, with routine testing to be carried out every 5 years;

[0163] 3) The protective layer on the surface of the component shall be maintained or replaced as required, and any defects that affect durability shall be dealt with in a timely manner;

[0164] 4) When abnormal monitoring data is found or phenomena affecting normal use are discovered, repairs should be carried out in a timely manner, and remedial measures should be taken if necessary.

[0165] 3.8 The monitoring and maintenance results of the anti-buoyancy project should be promptly reported to the design and engineering management departments, the property owner and the user.

[0166] 3.9 A database management system should be established for monitoring information, and results reports and raw data records should be submitted and archived together.

[0167] 4. Monitoring of anchoring components

[0168] 4.1 The number of anti-buoyancy components monitored shall comply with the provisions of Table 4.1.

[0169] Table 4.1 Number of Anti-buoyancy Components Monitored

[0170]

[0171] 4.2 The monitoring content and monitoring point layout of anti-buoyancy components shall comply with the following provisions:

[0172] 1) For non-prestressed anti-buoyancy components, stress and deformation, as well as deformation of the main structure at connection points, should be monitored;

[0173] 2) Stress and deformation, prestress loss, and anchor head corrosion should be monitored in prestressed members;

[0174] 3) Each profile should have no fewer than 3 observation points and no fewer than 2 observation profiles;

[0175] 4) Monitoring points should be set up at the locations where the buoyancy deformation is expected to be the greatest.

[0176] 4.3 The monitoring frequency shall comply with the following provisions:

[0177] 1) Monitoring should be conducted simultaneously with water level observation;

[0178] 2) After the force gauge or stress gauge is installed, it is advisable to measure once a day for the first 10 days, then once every 3 days for the next 20 days, and then once every 30 days thereafter.

[0179] 3) When changes in usage conditions cause a rapid change in the groundwater level, it should be measured promptly;

[0180] 4) Monitoring should be intensified in the event of heavy rain, continuous rainfall, vibration, or sudden changes in tensile test results.

[0181] 4.4 The monitoring period should be determined based on the initial state and service life of the anti-buoyancy components, and should not be less than 3 years.

[0182] 5. Groundwater monitoring

[0183] 5.1 The content of groundwater monitoring should be comprehensively determined based on the monitoring objectives, hydrogeological conditions, and engineering requirements. The layout of the monitoring network should be determined based on a thorough study of the exploration data and in conjunction with the design requirements. The monitoring profile should be able to control the groundwater state and the potential boundaries of groundwater changes, and should be arranged along the possible directions of change. It should also be carried out simultaneously with the monitoring of anti-buoyancy components.

[0184] 5.2 Groundwater monitoring methods shall comply with the following provisions:

[0185] 1) Set up dedicated groundwater level observation wells, or utilize existing boreholes, wells, natural groundwater outcrops, or adits;

[0186] 2) Pore water pressure and groundwater pressure can be monitored using pore water pressure gauges and manometers;

[0187] 3) When monitoring water quality using chemical analysis methods, the number of samplings should not be less than 4 times per year, and relevant indicators should be analyzed.

[0188] 4) Water level monitoring of surface water bodies that are hydraulically connected to groundwater should be carried out simultaneously with groundwater level monitoring;

[0189] 5) Water level monitoring should be carried out using self-recording water level gauges, electrical water level gauges, or multi-parameter automatic groundwater monitoring instruments;

[0190] 6) Two vertical measurements should be taken from the fixed point to the groundwater surface, and the two measurements and their average value should be recorded in the sampling record table.

[0191] 5.3 The installation and measurement of monitoring wells (holes) shall comply with the following regulations:

[0192] The structure of the monitoring well should meet the following requirements:

[0193] 1) The well casing should be made of a sturdy, corrosion-resistant material that does not pollute the groundwater, and its inner diameter should not be less than 50 mm;

[0194] 2) The depth should be determined based on the monitoring purpose, aquifer type, and thickness, and should be less than Zm below the burial depth;

[0195] 3) Filter pipes should be installed in the aquifer section below the dynamic water level, and the thickness of the filter layer should not be less than 50 mm;

[0196] 4) Confined water monitoring wells should be sealed in layers, and unconfined water monitoring wells should not penetrate the bottom plate of the impermeable layer below the unconfined aquifer.

[0197] 5) The observation well platform should be at least 0.5m above the ground, the wellhead should be covered, and there should be a protective railing around it.

[0198] 6) A leveling marker should be set up at an appropriate location near the monitoring well to check the elevation of the fixed point at the wellhead.

[0199] 5.4 The monitoring of bottom water pressure in the foundation slab of underground structures shall comply with the following provisions:

[0200] 1) The location of the monitoring area should be determined based on the geological and hydrogeological conditions of the site provided in the survey report;

[0201] 2) At least three sets of monitoring wells should be installed around the site where the structural load is relatively small;

[0202] 3) Each set of observation wells should be equipped with water level observation holes and pressure gauge holes at different depths to monitor water pressure at different depths and near the bottom of the plate;

[0203] 4) The water pressure distribution at different monitoring point elevations should be plotted using the observation data after the basic stabilization.

[0204] 5.5 Seepage pressure monitoring shall comply with the following provisions:

[0205] 1) The monitoring system should not be installed in a way that affects the functionality of the underground space;

[0206] 2) Monitoring points every 1000m 2 There should be no less than one such location, and each underground structure floor slab zone should have no less than four such locations.

[0207] 3) The fixed seepage pressure monitoring system should be evenly distributed within the pressure release zone.

[0208] 5.6 The monitoring frequency and time limit shall be determined according to the project construction stage and hydrological and meteorological conditions, and shall comply with the following provisions:

[0209] 1) The long-term monitoring period should not be less than one hydrological year, and water level monitoring should be conducted at least once a year during the wet season and dry season;

[0210] 2) Pore water pressure monitoring should be conducted according to project requirements;

[0211] 3) Groundwater pressure monitoring during the construction period should continue until the project load exceeds the buoyancy, at which point monitoring can be stopped;

[0212] 4) The monitoring dates and times should be consistent for all water level monitoring points within the same hydrogeological unit;

[0213] 5) Monitoring should be intensified during the period of accelerated deformation or during heavy rain and floods.

[0214] 6. Monitoring and maintenance of drainage pressure limiting method, water-isolation pressure control method and water discharge pressure reduction method. The monitoring content should include the initial water level inside and outside the building project, the initial value of the surrounding ground settlement, and the deformation of the protected object.

[0215] 6.1 Environmental background values ​​should be measured one week before the system officially begins operation.

[0216] 6.2 The pressure-reducing drainage system should be equipped with dual power supplies or a standby generator set, and the two power supplies should be able to switch in a timely manner.

[0217] 6.3 When the groundwater level significantly exceeds the design control level, it should be pumped out in a timely manner.

[0218] 6.4 During the monitoring process, monitoring data should be compiled in a timely manner, and potential problems should be predicted and dealt with promptly.

[0219] 6.5 The maintenance of drainage pressure limiting wells shall comply with the following provisions:

[0220] 1) Regular maintenance should be carried out on drainage pressure limiting wells and their facilities, and any damage to the facilities must be repaired in a timely manner;

[0221] 2) The depth of the drainage pressure limiting well shall be measured no less than once every two years, and the well shall be cleaned in time when the silt in the well submerges the filter pipe;

[0222] 3) The permeability sensitivity test of the drainage pressure limiting well shall be conducted at least once every 5 years. When the water level recovery time exceeds 15 minutes after injecting 1m of water into the well, the well shall be flushed.

[0223] 4) A basic information table should be established for each drainage pressure limiting well. The cancellation or change of monitoring wells should be recorded in the original monitoring well table. A new table should be established for each newly replaced monitoring well.

[0224] 6.6 The pressure limiting method, water isolation pressure control method, and water discharge pressure reduction method shall adhere to the principle of pressure reduction on demand and formulate detailed pressure reduction and pressure reduction operation plans; when the surrounding environment has a significant impact, the operation plan shall be adjusted or modified in a timely manner.

[0225] 6.7 The drainage capacity should meet the requirements when all pressure-reducing facilities are in operation, and the pumped water should be discharged outside the affected area.

[0226] 7. Data Compilation

[0227] 7.1 The compilation, statistics and analysis of monitoring data for anti-buoyancy projects shall be carried out in accordance with the current national standards GB50026 "Code for Engineering Surveying", JGJ8 "Code for Measurement of Building Deformation" and CJJ76 "Code for Dynamic Monitoring of Urban Groundwater".

[0228] 7.2 Monitoring data should reflect the relationship between monitoring parameters and monitoring time, and monitoring briefings, annual monitoring reports and general reports should be submitted.

[0229] 7.3 The monitoring report shall include the following:

[0230] 1) Overview of the project's anti-buoyancy measures, including the names of the design, construction, and supervision units;

[0231] 2) Monitoring purpose and content, monitoring date, report completion date, and signatures of monitoring personnel, reviewers, and approvers;

[0232] 3) Monitoring basis, layout of measuring points, monitoring methods, monitoring accuracy, model, specifications and calibration data of monitoring instruments;

[0233] 4) Monitoring data and historical changes at each stage, data processing basis and compilation results, monitoring parameters and time curves;

[0234] 5) Analyze and evaluate the monitoring results, determine the anti-buoyancy stability state based on the monitoring data, and predict the trend of change;

[0235] 6) Monitoring conclusions and recommendations.

[0236] 7.4 The monitoring results report should include the following figures:

[0237] 1) Main geological map of the monitoring area, monitoring network layout map, and installation map of main monitoring items;

[0238] 2) Deformation duration curves, planar vector diagrams, duration curves of groundwater level, water pressure, water quality, water quantity and pore water pressure, and duration curves of rainfall;

[0239] 3) Other monitoring data analysis charts.

[0240] It should be noted that embodiments of the present invention can be implemented in hardware, software, or a combination of both. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by a suitable instruction execution system, such as a microprocessor or dedicated-design hardware. Those skilled in the art will understand that the above-described devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuitry such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field-programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of the above-described hardware circuitry and software, such as firmware.

[0241] In summary, this prestressed anti-buoyancy anchor bolt construction method based on digital simulation involves: 1) a machine operator moving the drilling rig to the anchor bolt location and erecting it; 2) surveyors verifying the hole position a second time, and proceeding to the next step after confirmation; 3) starting the drilling rig to drill to the designed depth; 4) installing the anchor cable, ensuring the free section of the cable is protected against corrosion and isolated; 5) employing a secondary grouting method, with the grouting pipe end 150mm from the bottom of the hole, ensuring the pipe opening is always submerged in mortar during grouting; 6) sealing the hole opening after the grout is full, and grouting is continued at a pressure of 0.4–0.6 MPa for 10 minutes; 7) when the anchor body test block reaches 80% of the design strength, prestressing can be performed, with the prestress value generally being 75%–80% of the design anchoring force, applied in stages; 8) locking the anchor bolt when there is no significant attenuation of the anchor cable prestress; 9) compensating tensioning should be performed after locking if there is significant stress loss; 10) significantly improving the anti-buoyancy capability of building engineering.

[0242] The above description is only a specific embodiment of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A prestressed anti-floating anchor construction method based on digital simulation, characterized by The method comprises the following steps: Step 1: constructing a finite element model of the building anti-floating anchor by model construction software; and making a simulation model of the original building structure and the existing foundation treatment method according to a certain scale reduction; Step 2: testing the prestress of the anti-floating anchor by a prestress testing device; Step 3: constructing a visual three-dimensional model of the anti-floating anchor construction by three-dimensional software, simulating the construction process based on the simulation model and the three-dimensional model based on BIM technology, and performing the construction according to the simulation scheme; the drilling machine is moved to the anchor position by machine operation workers, and the anchor is erected; the hole position is rechecked by measurement personnel, and the next step is performed after no error is found; Step 4: starting the drilling machine to form a hole, drilling to the designed depth; placing the anchor cable, and performing corrosion and isolation treatment on the free section of the anchor cable; The secondary grouting method is adopted, the grouting pipe end is 150 mm away from the hole bottom, the pipe opening is always buried in the mortar during grouting, the hole opening is blocked after the slurry is filled, and the slurry is supplemented at a pressure of 0.4-0.6 MPa for 10 minutes; Step 5: when the strength of the anchor body and the condition test block reaches 80% of the designed strength, prestress tensioning can be performed, the prestress value is generally 75%-80% of the designed anchoring force, and the anchor cable is locked when the prestress does not obviously attenuate; if there is obvious stress loss after locking, compensation tensioning should be performed; The simulation method is as follows: Early data collection, including the geographic information of the anti-floating anchor construction site, the three-dimensional size of the anchor and the building, and the anti-floating anchor construction scheme; the geographic information of the anti-floating anchor construction site includes the plane coordinates and elevation point coordinates of the anti-floating anchor construction site, and the anti-floating anchor construction scheme includes the anti-floating anchor construction time, the anti-floating anchor construction area division, the anti-floating anchor construction machinery arrangement and the anti-floating anchor construction task; An anti-floating anchor construction submodel is established based on the collected data based on a BIM platform, including an anti-floating anchor construction site submodel, an anchor submodel and an anti-floating anchor construction machinery submodel; the anti-floating anchor construction submodel is generated by different modeling software, wherein the anti-floating anchor construction site submodel is generated by Civil3D software, the anchor submodel is established by Revit software, and the anti-floating anchor construction machinery submodel is made by Inventor software; Anti-floating anchor construction process information is obtained from the anti-floating anchor construction scheme, the anti-floating anchor construction submodel data and the anti-floating anchor construction process information are imported into an anti-floating anchor construction simulation platform to assemble an anti-floating anchor construction model; the anti-floating anchor construction simulation platform is a Navisworks platform, each anti-floating anchor construction submodel data is converted into IFC standard format data, the anti-floating anchor construction process information is created and stored in MicrosoftProject in a non-IFC standard format, and then the above data information is imported into the Navisworks platform to assemble the anti-floating anchor construction model on the Navisworks. The anti-floating anchor construction model is used to produce an anti-floating anchor construction simulation animation; the production process of the anti-floating anchor construction simulation animation comprises associating and matching anti-floating anchor construction progress information with an anti-floating anchor construction model, animation design of anti-floating anchor construction machinery operation, and rendering of an anti-floating anchor construction scene; The associating and matching of the anti-floating anchor construction progress information with the anti-floating anchor construction model means simulating the anti-floating anchor construction progress at different time intervals, establishing a specific anti-floating anchor construction time arrangement and a corresponding relationship between the anti-floating anchor construction process, and the method comprises: establishing a specific paving progress arrangement table by using Microsoft Project, which is refined to each paving unit of each layer, i.e. each paving unit is established with an anti-floating anchor construction task corresponding to itself, and is associated with the action and time of the anti-floating anchor construction machinery, and then the anti-floating anchor construction progress data is imported into the Timeliner module in Navisworks; The animation design of the anti-floating anchor construction machinery operation comprises working animation of the anti-floating anchor construction machinery and scheduling of the anti-floating anchor construction vehicles, wherein the working animation of the anti-floating anchor construction machinery is obtained by capturing the anti-floating anchor construction machinery and using the operation command simulation by the Animation module, and the scheduling of the anti-floating anchor construction vehicles is obtained by the Animation module through unified scheduling simulation of the anti-floating anchor construction machinery vehicles; and the rendering method of the anti-floating anchor construction scene is that the animation of the anti-floating anchor construction machinery operation is added to the Timeliner in the post-processing, and the anti-floating anchor construction scene is rendered by using the Presenter module.

2. The construction method of prestressed anti-floating anchor based on digitalized simulation according to claim 1, characterized in that: The anchor rod is preferably constructed after the completion of the concrete cushion layer of the underground structure bottom plate.

3. The construction method of prestressed anti-floating anchor based on digitalized simulation according to claim 1, characterized in that: During construction, water seepage test should be conducted on the hole wall around the hole. When the water seepage rate of the hole wall around the anchoring section is greater than 0.01 m 3 / min, consolidation grouting method or other filling treatment should be adopted.

4. The construction method of prestressed anti-floating anchor based on digitalized simulation according to claim 1, characterized in that: The drilling and hole cleaning method of the anti-floating anchor rod is as follows: 1) The anchor rod position should be rechecked before the drilling machine is positioned, and the drilling machine positioning should be accurate, horizontal, vertical and stable; 2) The allowable deviation of the drilling verticality is preferably less than 1%, and the allowable deviation of the hole position should be ±50mm; The casing wall protection drilling is preferably used in the unstable stratum; The hole debris should be removed after the bar body is put into the hole and before grouting, and the hole collapse and hole wall deformation should be treated.

5. The digitalized simulation based construction method of pre-stressed anti-floatation anchor as claimed in claim 1 wherein: The bar body production, storage and placement method is as follows: (1) The bar body, supporting plate, nut and other components should be prepared according to the design requirements, and a centering structure should be attached to the bar body; (2) The bar body should be prevented from rusting, damaging, soil or oil stain adhering and excessive deformation during the assembly, storage and transportation processes; (3) The grouting pipe is placed into the hole together with the bar body, and the bar body should not be less than 1.2 times the design anchoring length out of the bottom surface of the foundation pit; (4) The bar body should be fixed at the hole opening, and should not be shaken, pulled or collided before the grouting body reaches 70% of the design strength.

6. The digitalized simulation based construction method of pre-stressed anti-floatation anchor as claimed in claim 1 wherein: The anchor rod grout preparation and grouting method is as follows: The sand diameter of the mortar should not be greater than 2mm, and the stirring time should not be less than 1min, and the mortar should be used immediately after stirring; The grouting pump should be tested before use, and the pipeline joints should be connected firmly and sealed; The grouting pipe should be inserted into the hole bottom and then pulled up by 50mm-100mm before grouting, and the grouting should be continuous. The grout should overflow from the hole in the first grouting, and the second grouting should be carried out 4-8 hours after the first grouting. The pressure should be stabilized for 5 minutes when the pressure reaches 1.5 MPa. Measures should be taken to avoid the influence of water pumping on the quality of grouting when there are measures to reduce water.

7. The digitalized simulation based construction method of pre-stressed anti-floatation anchor as claimed in claim 1 wherein: The tensioning and locking method of prestressed anchor rod is as follows: The tensioning equipment should be calibrated and calibrated before the anchor rod tensioning. The bearing surface of the anchor head pedestal should be flat. The compressive strength value of the grouting body and the pedestal concrete during tensioning should meet the provisions of the table. The anchor rod should be pre-tensioned 1-2 times before formal tensioning, with a tension of 10%-15% of the design value. When the locking load of load dispersion type anchor rod is equal to the design value of uplift resistance, parallel jack groups should be used to tension and lock each unit simultaneously. When the locking load is less than the design value of uplift resistance, the bottom of the hole should be drilled towards the top, and each unit should be tensioned and locked in sequence, with equal stress. The tensioning should be uniform and orderly to avoid the adverse effects of local area concentrated tensioning on adjacent anchor rods. The tendon, jack or other anchor clamps should not be disturbed during tensioning. The tensioning load and deformation should be recorded completely, and the anchor head should be sealed in time after tensioning is completed.

8. The digitalized simulation based construction method of pre-stressed anti- floating anchor according to claim 1, characterized in that: The waterproofing and corrosion prevention construction methods during anchor rod construction are as follows: The selected materials should meet the relevant provisions of "Technical Code for Waterproofing of Underground Engineering" GB50108 and the design requirements. Modified asphalt paste, modified asphalt waterproofing membrane and hot melt connection should be used. When groundwater leakage is found after the trench is cleaned, measures should be taken to stop water to ensure that there is no open water around the anchor rod. The anchor body at the end of the anchor rod should be chiseled to the dense part, and the floating ash or slurry on the tendon should be removed, and then the polymer cement waterproofing mortar should be leveled to the design requirement top elevation. Waterproofing should be applied according to the design requirements. The modified asphalt should be poured into the groove after hot melting, and the waterproofing membrane should be hot melted and pasted in time. The length of the anchor tendon coating should not be less than 60 mm, and the modified asphalt should be hot sealed.

9. The digitalized simulation based construction method of pre-stressed anti- floating anchor according to claim 1, characterized in that: The finished product protection method of anti-floating anchor rod is as follows: The tendon extending out of the working surface should be coated with plain cement slurry to avoid disturbing the anchor body and tendon during the construction of the underground structure bottom plate. The tendon should be inspected before concrete pouring, and secondary corrosion prevention should be carried out. The construction method of existing engineering anti-floating treatment is as follows: The anchor rod construction scheme should be specially demonstrated for complex geological conditions and surrounding environment, and construction disturbance of sensitive structures. The prestressed member should be tensioned in stages. The construction should not damage the existing structure and member, and the existing structure and member should be monitored.

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