Rectangular pipe jacking construction stratum disturbance monitoring method based on optical fiber sensing technology

Abstract

The invention relates to a rectangular pipe jacking construction stratum disturbance monitoring method based on an optical fiber sensing technology. The method comprises the following steps that a monitoring element is manufactured; determining a deformation monitoring range of a soil body around the rectangular pipe-jacking tunnel according to the section position of the rectangular pipe-jacking tunnel and tunneling line measurement setting-out, and positioning the burying position of a monitoring element; constructing the burying position of the monitoring element; burying monitoring elements to form a monitoring network; the monitoring element is connected with a demodulator, and the strain of the monitoring element is continuously monitored along with the tunneling process of the rectangular pipe jacking machine and the jacking process of the rectangular pipe jacking pipe joint; and analyzing a strain monitoring result of the monitoring element, and calculating soil deformation. According to the invention, the monitoring elements are buried in the soil body around the rectangular jacking pipe to form a monitoring network of three-dimensional deformation of the soil body, so that the stratum disturbance of the rectangular jacking pipe construction can be monitored in real time in an omnibearing, long-distance and continuous manner, and a reliable basis is provided for risk prediction and prevention and control of the rectangular jacking pipe construction.

Description

Technical Field

[0001] The invention relates to the technical field of rectangular pipe jacking construction monitoring, and in particular to a method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology. Background Art

[0002] The rectangular pipe jacking method is widely used in the construction of municipal infrastructure such as urban integrated pipeline corridors, street crossings, and vehicle tunnels due to its low cost, small environmental impact, high cross-section utilization rate, and strong adaptability to shallow overburden layers.

[0003] As a dark excavation method, the rectangular pipe jacking method is prone to disturbing the strata due to factors such as the loading, unloading, and over-excavation of the soil in front of the rectangular pipe jacking machine during excavation, as well as the friction-reducing grouting, pipe-soil friction, and pipe segment deflection during the rectangular pipe jacking process. According to the stress state of the soil, the disturbance of the soil caused by the rectangular pipe jacking method construction can be divided into squeezing disturbance, shear disturbance, unloading disturbance, grouting disturbance, etc. These disturbances directly threaten the safety of adjacent or surface structures (constructions). Especially under shallow burial conditions, when the friction between the rectangular pipe jacking machine head, pipe segment and the surrounding soil exceeds the restraining capacity of the surrounding soil, the rectangular pipe jacking machine and pipe segment will drive the upper soil to move forward as a whole, causing serious surface heave.

[0004] Traditional point-type strain gauges or displacement meters are often used in the existing rectangular pipe jacking construction soil deformation monitoring. Practice has shown that these inductive or mechanical sensors have poor waterproof and corrosion resistance, cumbersome manual installation, easy damage or drift during use, weak measurement stability, low accuracy, low level of intelligent monitoring, etc., and cannot achieve large-scale and long-distance monitoring. These problems affect the ability of engineering personnel to identify the risks of rectangular pipe jacking construction. Summary of the invention

[0005] In view of the technical problems existing in the prior art, the purpose of the present invention is to provide a method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology, so as to solve the problem that the existing method for monitoring soil deformation in rectangular pipe jacking construction cannot achieve large-scale and long-distance monitoring, which affects the ability of engineering personnel to identify the risks of rectangular pipe jacking construction.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology comprises the following steps:

[0008] S1: Make monitoring components;

[0009] S2: According to the cross-sectional position of the rectangular pipe jacking tunnel and the measurement and layout of the excavation route, the deformation monitoring range of the soil around the rectangular pipe jacking tunnel is determined, and the buried position of the monitoring element is located;

[0010] S3: construct the buried position of the monitoring element;

[0011] S4: bury monitoring elements to form a monitoring network;

[0012] S5: Connect the monitoring element to the demodulator, and continuously monitor the strain of the monitoring element as the rectangular pipe jacking machine and the rectangular pipe jacking section are being driven forward;

[0013] S6: Analyze the strain monitoring results of the monitoring elements and calculate the soil deformation.

[0014] As a preferred embodiment, in step S1, the method for making the monitoring element is: making sensing tube fittings of different lengths, evenly arranging grooves in the circumference of the sensing tube fittings, and the grooves extending along the axial direction of the sensing tube fittings; making polyurethane tight sheathed sensing optical cables of different lengths, and arranging the polyurethane tight sheathed sensing optical cables in the grooves.

[0015] As a preferred embodiment, before the polyurethane tight sheathed sensing optical cable is arranged in the groove, a prestress is applied to the sensing optical cable by an optical fiber stretcher.

[0016] As a preferred embodiment, in step S2, the method for locating the buried position of the monitoring element is: starting from the section 6m away from the starting well of the rectangular top pipe, at a position 2m away from the two side walls of the rectangular top pipe, locate the vertical first installation hole in the direction of the receiving well at an equal interval of 10m;

[0017] Starting from the section 6m away from the rectangular jacking starting well, locate the second vertical installation holes at equal intervals of 10m directly above the axis of the rectangular jacking pipe towards the receiving well;

[0018] Starting from the section 1m away from the rectangular jacking pipe starting well, position the transverse horizontal installation grooves above the rectangular jacking pipe at equal intervals of 10m towards the receiving well.

[0019] As a preferred embodiment, in step S3, the method for constructing the buried position of the monitoring element is as follows: drilling a hole at a vertical first mounting hole position 2m away from the two side walls of the rectangular top pipe to form a vertical first mounting hole perpendicular to the rectangular top pipe, and the depth of the vertical first mounting hole is the sum of the designed buried depth of the bottom of the rectangular top pipe and 1 / 2 of the pipe section height; drilling a hole at a vertical second mounting hole position directly above the axis of the rectangular top pipe to form a vertical second mounting hole perpendicular to the rectangular top pipe, and the depth of the vertical second mounting hole is 0.9 times the thickness of the soil covering the rectangular top pipe machine; digging a groove at a transverse horizontal mounting groove position located above the rectangular top pipe to form a transverse horizontal mounting groove perpendicular to the axis of the rectangular top pipe, the transverse horizontal mounting groove is located 0.5m below the ground, and the length of the transverse horizontal mounting groove is the sum of twice the buried depth of the bottom of the rectangular top pipe and the width of the rectangular top pipe section plus 0.3m.

[0020] As a preferred embodiment, in step S4, the method of burying monitoring elements to form a monitoring network is as follows: monitoring elements are respectively buried in the vertical first mounting hole, the vertical second mounting hole and the transverse horizontal mounting groove to form a monitoring network, a cement ash layer is laid on the bottom of the transverse horizontal mounting groove, the monitoring elements buried in the transverse horizontal mounting groove are connected to the lead-out section through a connecting pipe and led out of the ground, and a protective pier is built, and the vertical first mounting hole, the vertical second mounting hole and the transverse horizontal mounting groove are backfilled.

[0021] As a preferred method, the method for backfilling the vertical first mounting hole, the vertical second mounting hole and the horizontal mounting groove is: use fine sand or mortar mixed with cement and bentonite to backfill the gap between the monitoring element and the vertical first mounting hole and the vertical second mounting hole; when backfilling the horizontal mounting groove, first use fine sand or mortar mixed with cement and bentonite to backfill to the top of the monitoring element, and then continue to backfill the soil to the original ground elevation.

[0022] As a preferred embodiment, in step S6, the method for calculating soil deformation is: taking any section of the monitoring element, according to the strain values ​​ε1 and ε2 generated by two symmetrical sensing optical cables when the monitoring element is bent, the diameter d of the sensing sensing pipe of the monitoring element, and according to the deformation boundary conditions of the monitoring element, a calculation formula (1) for the deflection ω of any section of the monitoring element is established, and then according to the strain monitoring values ​​of each monitoring element, the soil deformation in the monitoring area is calculated by using a numerical integration method;

[0023]

[0024] In general, the present invention has the following advantages:

[0025] The present invention discloses a method for monitoring stratum disturbance during rectangular pipe jacking construction based on optical fiber sensing technology. By setting a three-dimensional monitoring network around the rectangular pipe jacking, long-distance, all-round, real-time online monitoring of soil deformation around the rectangular pipe jacking construction process is achieved, providing a useful reference for risk identification and safety control of rectangular pipe jacking construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Form a layout diagram of the monitoring network for buried monitoring elements;

[0027] Figure 2 Form a plan layout of the monitoring network for buried monitoring elements;

[0028] Figure 3 Form a cross-sectional layout of the monitoring network for buried monitoring elements;

[0029] Figure 4 is a cross-sectional schematic diagram of the monitoring element;

[0030] Figure 5 This is a large-scale drawing of the polyurethane tight sheathed sensor optical cable;

[0031] Figure 6 A schematic diagram of the structure of the monitoring element arranged in the horizontal installation groove;

[0032] Figure 7 This is a large-scale drawing of the 90° connection pipe (elbow) of the PVC pipe;

[0033] Figure 8 The figure is a schematic diagram of the calculation of the bending deformation of the monitoring element arranged in the vertical first mounting hole, the vertical second mounting hole and the transverse horizontal mounting groove.

[0034] In the figure: rectangular jacking pipe section 1, rectangular jacking tunneling machine 2, vertical sensor tube 3, lateral sensor tube 4, BOTDR demodulator 5, rectangular jacking starting well 6, backrest 7, jack 8, rectangular jacking receiving well 9, polyurethane tight sheathed sensor cable 31, sensor tube fittings 32, lateral sensor tube horizontal section 41, lead-out section 42, connecting pipe 43. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below in conjunction with specific implementation methods.

[0036] like Figure 1-Figure 7 As shown, the present embodiment provides a method for monitoring ground disturbance in rectangular pipe jacking construction based on optical fiber sensing technology. The monitoring elements used in the monitoring method include a plurality of vertical sensing tubes 3 and horizontal sensing tubes 4. The vertical sensing tubes 3 and horizontal sensing tubes 4 are composed of four polyurethane tight sheathed sensing optical cables 31 with an outer diameter of 2 mm and uniformly pasted on the circumference. The sensing tube fitting 32 is made in the axial prefabricated groove of the sensing tube fitting 32, and the adhesive is epoxy resin glue. Among them, the length of the vertical sensing tube 3 located at 2m on both sides of the rectangular top pipe wall is the sum of the designed buried depth of the bottom of the rectangular top pipe and the height of 1 / 2 of the rectangular top pipe section. Starting from the section 6m away from the rectangular top pipe starting well, on both sides of the rectangular top pipe, 2m away from the side wall of the rectangular top pipe and above the axis of the rectangular top pipe, it is linearly buried in the direction of the receiving well at an equal interval of 10m. The length of the vertical sensing tube 3 above the axis of the rectangular top pipe is 0.9 times the thickness of the soil covering the rectangular top pipe machine; the horizontal sensing tube 4 is L-shaped as a whole, and is composed of a horizontal sensing tube horizontal section 41 with a length of twice the sum of the buried depth of the bottom of the rectangular top pipe and the width of the rectangular top pipe section and a lead-out section 42 with a length of 0.5m, and a PVC pipe 90° connection pipe (elbow) 43 ( Figure 7), the horizontal sensing sensing pipe 4 is distributed at a horizontal interval of 10m, the horizontal section 41 of the horizontal sensing sensing pipe is buried at a depth of 0.5m, and enters the original soil layer, starting from the section 1m away from the rectangular jacking starting well, and arranged perpendicular to the axis of the rectangular jacking pipe at an equal interval of 10m in the direction of the receiving well. After the burial of each monitoring element is completed, a light loss detection is required using a light nanometer. After no abnormality is found, they are all connected to the BOTDR demodulator 5 and connected to a computer for real-time monitoring.

[0037] like Figure 8 As shown in the figure, based on the strain monitoring results of each monitoring element and according to the relevant theories of material mechanics, the deformation of the soil around the rectangular jacking pipe is indirectly determined by calculating the deflection of the monitoring element, which is specifically:

[0038] According to the strain values ​​ε1 and ε2 generated by the sensing optical cables symmetrically pasted on both sides of the monitoring element when it is bent, the diameter d of the sensing tube fitting 32, and considering the deformation boundary conditions of the sensing optical cable, a calculation formula for the deflection ω of any section of the sensing tube fitting 32 is established. Then, according to the strain monitoring values ​​of each sensing optical cable, the numerical integration method is used to calculate the soil deformation in the monitoring area.

[0039] The embodiment of the present invention discloses a method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology, which comprises the following steps:

[0040] S1: According to the cross-sectional position of the rectangular pipe jacking tunnel and the measurement and layout of the excavation route, combined with the provisions on the layout of monitoring points in "9.8 Monitoring and Deformation Control" of the Guangdong Provincial Standard "Technical Code for Rectangular Pipe Jacking Engineering" (DBJ / T 15-229-2021), determine the monitoring range of soil deformation around the rectangular pipe jacking tunnel, and locate the buried positions of the vertically and horizontally distributed monitoring elements, which include vertical sensor tubes 3 and horizontal sensor tubes 4.

[0041] 1) Layout principle of vertical sensing sensor pipe 3: Starting from the section 6m away from the rectangular jacking starting well, it is buried linearly in the direction of the receiving well at 10m intervals at 2m away from the side wall of the rectangular jacking pipe on both sides of the rectangular jacking pipe and directly above the axis of the rectangular jacking pipe. The hole depth of the vertical sensing sensor pipe 3 at 2m away from the two side walls of the rectangular jacking pipe is the sum of the designed buried depth of the bottom of the rectangular jacking pipe and 1 / 2 of the pipe section height. The hole depth of the vertical sensing sensor pipe 3 at the center axis is 0.9 times the thickness of the soil covering the rectangular jacking machine. Through the flexural deformation of the vertical sensing sensor pipe 3, the horizontal displacement of soil at different depths caused by shear disturbances such as excavation of the jacking machine and jacking of the pipe section can be obtained.

[0042] 2) Layout principle of the lateral sensing tube 4: Starting from the section 1m away from the starting well of the rectangular jacking pipe, it is arranged perpendicular to the axis of the rectangular jacking pipe at an equal interval of 10m towards the receiving well. The lateral sensing tube 4 is buried 0.5m deep and ensures that it enters the original soil layer. The length is twice the sum of the burial depth of the bottom of the rectangular jacking pipe and the width of the rectangular jacking pipe section.

[0043] S2: Drill holes at the three points of the vertical sensing sense tube determined in S1 above, that is, drill holes at a distance of 2m from the two side walls of the rectangular top tube to obtain a first vertical installation hole 2m away from the two side walls of the rectangular top tube, which is vertical to the rectangular top tube; drill holes at the buried position located directly above the axis of the rectangular top tube to obtain a second vertical installation hole directly above the axis of the rectangular top tube, which is vertical to the rectangular top tube, with a hole diameter of 100mm; excavate a transverse horizontal installation groove at the proposed buried position of the transverse sensing sense tube 4 determined in S1 above to obtain a transverse horizontal installation groove formed above the rectangular top tube, which is horizontal to the rectangular top tube, with a depth of 0.5m and a width of 0.3m. The length is 0.3m higher than the sum of twice the buried depth of the bottom of the rectangular top tube and the width of the rectangular top tube section; clean the transverse horizontal installation groove after excavation.

[0044] S3: Determine the number of vertical sensing tubes 3 and horizontal sensing tubes 4 according to the top length of the rectangular top pipe and the layout principle of the monitoring elements described in S1, and then make vertical sensing tubes 3 and horizontal sensing tubes 4 of different lengths: the sensing tube fittings 32 used in the vertical sensing tubes 3 and the horizontal sensing tubes 4 are all made of The PVC tube has a wall thickness of 5mm and is provided with four longitudinal prefabricated grooves evenly distributed around the circumference. The transverse sensing tube 4 is composed of a transverse sensing tube horizontal section 41, a lead section 42, and a connecting pipe 43. The sensing optical cable used in the vertical sensing tube 3 and the transverse sensing tube 4 is a polyurethane sheathed sensing optical cable 31 with an outer diameter of 2mm. First, a fiber optic stretcher is used to apply a certain prestress to the polyurethane sheathed sensing optical cable 31, and several polyurethane sheathed sensing optical cables 31 are pasted into the axial prefabricated grooves of several sensing tube fittings 32 to form the vertical sensing tube 3 and the transverse sensing tube 4 (such as Figure 4 As shown), when pasting, ensure that a polyurethane sheathed sensor optical cable 31 is pasted in each prefabricated groove of the sensor tube fitting 32, and the adhesive used is epoxy resin glue. The effective pasting length of each polyurethane sheathed sensor optical cable 31 is at least 80% of the length of the sensor tube fitting 32.

[0045] S4: bury the monitoring elements, bury the prepared vertical sensing tube 3 in the vertical first installation hole and the vertical second installation hole completed in the above S2 in turn, lower the prepared transverse sensing tube 4 into the transverse horizontal installation groove excavated in the above S2, and lay a layer of cement ash on the bottom of the groove before lowering the transverse sensing tube 4; the end of the horizontal section 41 of the transverse sensing tube is connected to the vertical 2m long lead-out section 42 through a 90° elbow (connecting pipe 43), lead the sensing optical cable out of the ground and build a protective pier.

[0046] Among the monitoring elements used, both the vertical sensing tube 3 and the horizontal sensing tube 4 are composed of a sensing tube fitting 32 and a circumferentially evenly distributed polyurethane tight sheathed sensing cable 31. The polyurethane tight sheathed sensing cable 31 is attached to the flexible sensing tube fitting 32 to achieve coordinated deformation of the sensing cable and the surrounding soil. By sensing the strain in different directions of the sensing tube fitting 32, the soil deformation is monitored in all directions. The use of monitoring elements not only ensures the safety of the sensing cable, but also ensures the reliability of the rock and soil deformation monitoring data, avoiding the problems of sensing cable breakage and monitoring system failure caused by direct burial of the sensing cable.

[0047] Through the above-mentioned arrangement of monitoring elements, a linear, surface and volume quantitative monitoring network of soil deformation at key positions around the rectangular pipe jacking is formed to realize long-distance, all-round real-time online monitoring of soil deformation around the rectangular pipe jacking construction process, providing a useful reference for risk identification and safety control of rectangular pipe jacking construction.

[0048] Several transverse sensing tubes are buried in the soil above the rectangular jacking pipe, which can effectively monitor the settlement or uplift deformation of the soil at different sections during the excavation of the jacking machine and the subsequent jacking of the pipe sections.

[0049] Vertical sensing tubes are linearly arranged along the jacking direction on both sides of the rectangular jacking pipe cross section and the central axis. By monitoring the deformation characteristics of the two sides of the jacking pipe and the overlying soil layer in the horizontal direction during the rectangular jacking pipe jacking construction, a basis is provided for the identification and prevention of construction risks such as jacking pipe backfill and pipe section deflection. The deformation law of soil in the rectangular jacking pipe construction process is fully revealed through line, surface and body deformation monitoring.

[0050] S5: Backfill the first vertical installation hole, the second vertical installation hole and the horizontal installation groove, and use fine sand or mortar mixed with cement and bentonite to backfill the gap between the monitoring element and the first vertical installation hole and the second vertical installation hole to ensure good coupling between the monitoring element and the surrounding soil; when backfilling the horizontal installation groove, first use fine sand or mortar mixed with cement and bentonite to backfill to the top of the monitoring element, and then continue to backfill the soil to the original ground elevation; after the sensor optical cable of each monitoring element is led out of the ground, the monitoring protection pier is promptly built to prevent damage to the sensor optical cable.

[0051] S6: Connect the sensor optical cables of each monitoring element to the AQ8603 BOTDR demodulator 5. As the rectangular pipe jacking machine 2 starts to excavate from the starting well 6, and the subsequent rectangular pipe jacking section 1 is pushed into the receiving well 9 by the pushing system composed of the backrest 7 and the jack 8 to complete the whole process of pipe jacking construction, the strain of the buried monitoring elements is continuously monitored in real time.

[0052] S7: Calculate soil deformation based on the strain monitoring results of each monitoring element: Since the monitoring element is well coupled with the soil, the deformation value of the surrounding soil during the rectangular jacking process is determined by calculating the deflection of the monitoring element, such as Figure 8 As shown, take any section of the monitoring element, according to the strain values ​​ε1 and ε2 generated by the two sensing optical cables symmetrically attached on both sides of the monitoring element when the monitoring element is bent, the diameter d of the sensing sensing pipe 32 of the monitoring element, and consider the deformation boundary conditions of the monitoring element, establish the calculation formula (1) for the deflection ω of any section of the monitoring element, and then use the numerical integration method to calculate the soil deformation in the monitoring area according to the strain monitoring value of each monitoring element. The calculation formula is as follows:

[0053]

[0054] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology, characterized in that: The following steps are involved: S1: Make monitoring components; S2: According to the cross-sectional position of the rectangular pipe jacking tunnel and the measurement and layout of the excavation route, the deformation monitoring range of the soil around the rectangular pipe jacking tunnel is determined, and the buried position of the monitoring element is located; S3: construct the buried position of the monitoring element; S4: bury monitoring elements to form a monitoring network; S5: Connect the monitoring element to the demodulator, and continuously monitor the strain of the monitoring element as the rectangular pipe jacking machine and the rectangular pipe jacking section are being driven forward; S6: Analyze the strain monitoring results of the monitoring elements and calculate the soil deformation.

2. A method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology according to claim 1, characterized in that: In step S1, the method for making the monitoring element is: making sensing tube fittings of different lengths, evenly arranging grooves in the circumference of the sensing tube fittings, and the grooves extending along the axial direction of the sensing tube fittings; making polyurethane tight sheathed sensing optical cables of different lengths, and arranging the polyurethane tight sheathed sensing optical cables in the grooves.

3. A method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology according to claim 2, characterized in that: Before the polyurethane tight sheathed sensing optical cable is arranged in the groove, a prestress is applied to the sensing optical cable by an optical fiber stretcher.

4. A method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology according to claim 1, characterized in that: In step S2, the method for locating the buried position of the monitoring element is: starting from the section 6m away from the rectangular jacking starting well, at a position 2m away from the two side walls of the rectangular jacking pipe, locate the vertical first installation hole in the direction of the receiving well at an equal interval of 10m; Starting from the section 6m away from the rectangular jacking starting well, locate the second vertical installation holes at equal intervals of 10m directly above the axis of the rectangular jacking pipe towards the receiving well; Starting from the section 1m away from the rectangular jacking pipe starting well, position the transverse horizontal installation grooves above the rectangular jacking pipe at equal intervals of 10m towards the receiving well.

5. A method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology according to claim 4, characterized in that: In step S3, the method for constructing the buried position of the monitoring element is: drilling a hole at the vertical first installation hole location located 2m away from the two side walls of the rectangular top pipe to form a vertical first installation hole perpendicular to the rectangular top pipe, and the depth of the vertical first installation hole is the sum of the designed buried depth of the bottom of the rectangular top pipe and 1 / 2 of the pipe section height; Drill a hole at the second vertical mounting hole position located just above the axis of the rectangular jacking pipe to form a second vertical mounting hole perpendicular to the rectangular jacking pipe. The depth of the second vertical mounting hole is 0.9 times the thickness of the soil covering the rectangular jacking machine. Dig a groove at the location of the transverse horizontal installation groove above the rectangular top pipe to form a transverse horizontal installation groove perpendicular to the axis of the rectangular top pipe. The transverse horizontal installation groove is located 0.5m below the ground. The length of the transverse horizontal installation groove is twice the sum of the buried depth of the bottom of the rectangular top pipe and the width of the rectangular top pipe section plus 0.3m.

6. A method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology according to claim 5, characterized in that: In step S4, the method of burying monitoring elements to form a monitoring network is as follows: monitoring elements are buried in the vertical first mounting hole, the vertical second mounting hole and the transverse horizontal mounting groove to form a monitoring network, a cement ash layer is laid on the bottom of the transverse horizontal mounting groove, the monitoring elements buried in the transverse horizontal mounting groove are connected to the lead-out section through a connecting pipe and led out of the ground, and a protective pier is built, and the vertical first mounting hole, the vertical second mounting hole and the transverse horizontal mounting groove are backfilled.

7. A method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology according to claim 6, characterized in that: The method for backfilling the vertical first mounting hole, the vertical second mounting hole and the horizontal mounting groove is: use fine sand or mortar mixed with cement and bentonite to backfill the gap between the monitoring element and the vertical first mounting hole and the vertical second mounting hole; when backfilling the horizontal mounting groove, first use fine sand or mortar mixed with cement and bentonite to backfill to the top of the monitoring element, and then continue to backfill the soil to the original ground elevation.

8. A method for monitoring stratum disturbance in rectangular pipe jacking construction based on optical fiber sensing technology according to claim 1, characterized in that: In step S6, the method for calculating soil deformation is as follows: take any section of the monitoring element, establish the calculation formula (1) for the deflection ω of any section of the monitoring element according to the strain values ​​ε1 and ε2 generated by the two symmetrical sensing optical cables when the monitoring element is bent, the diameter d of the sensing sensing pipe of the monitoring element, and the deformation boundary conditions of the monitoring element, and then calculate the soil deformation in the monitoring area using the numerical integration method according to the strain monitoring values ​​of each monitoring element;

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