A pipe jacking construction method for upper soft and lower hard composite strata

Abstract

A pipe jacking construction method for a composite stratum with soft upper and hard lower layers, which relates to the technical field of pipe jacking construction, mainly includes the following construction steps: After the pipe jacking machine is connected to the pipeline, the jacking construction is carried out, and the axis measurement target position at the machine head is monitored during the jacking construction process, and the axis offset and offset direction of the axis measurement target position are read: when the axis offset is within the error range, the jacking construction is carried out normally; when the axis offset exceeds the error range, the oil pressure of the jacking jack corresponding to the machine head offset direction is gradually increased to increase the elongation value of the jacking jack, until the machine head offset is adjusted to within the error range, and then the oil pressure of the jacking jack corresponding to the machine head offset direction is gradually reduced to be balanced with other jacking jacks. At the same time, during the jacking construction process, the upper soil layer at the front end of the jacking route is grouting reinforced.

Description

Technical Field

[0001] The invention relates to the technical field of pipe jacking construction, and in particular to a pipe jacking construction method for a composite stratum with soft upper strata and hard lower strata. Background Art

[0002] Urban construction is developing rapidly, and environmental protection requirements in municipal engineering are becoming increasingly higher. Therefore, it is necessary to add a new sewage collection system to the original sewage system. During the construction process, the existing underground sewage facilities cannot be destroyed, and the open excavation method cannot be used for sewage pipe construction. It has become inevitable to use non-excavation methods. There are currently three main non-excavation methods: traction method, jacking method, and shield method. The advantage of the traction method is that it pulls small-diameter pipes in the soil layer, which is greatly restricted by geology and pipe diameter; the advantage of the shield method is that it has large diameters and deep burial depths; for pipes with a diameter of 1 to 3 meters, the use of a jacking machine for jacking is more economical, the construction progress is controllable, and there is less interference to the outside world.

[0003] The pipe jacking method is divided into two types during the construction and excavation process: earth pressure balance and mud water balance. At present, the research on the pipe jacking method construction is mainly focused on geologically uniform and curved sections. For inhomogeneous sections, such as the upper geological layer is soft soil layers such as silt sand, and the lower layer is medium-hard rock, hard rock and other rock layers. In this kind of composite stratum with soft upper and hard lower layers, when the pipe jacking method is used for construction, how to ensure that the jacking line does not deviate and the pipeline does not break in the inhomogeneous rock layer with soft upper and hard lower layers is an important factor to be considered in pipe jacking construction. Summary of the invention

[0004] In order to solve the above problems of the prior art, the present invention provides a pipe jacking construction method for a composite stratum with soft upper part and hard lower part, which can ensure that the pipe jacking construction can be carried out safely and smoothly in the composite stratum with soft upper part and hard lower part.

[0005] The object of the present invention can be achieved by the following technical scheme: A pipe jacking construction method for a composite stratum with soft upper and hard lower layers, comprising the following construction steps:

[0006] S10, construction of the starting well and the hoisting well, the pipe jacking machine is hoisted and lowered into the starting well for installation;

[0007] S20, a shock absorbing plate is pasted between the front end of the first section of the pipe and the entire section of the contact surface of the pipe jacking machine;

[0008] S30, after the pipe jacking machine is connected to the pipeline, the jacking construction is carried out. During the jacking construction process, the axis measurement target position at the machine head is monitored, and the axis offset and offset direction of the axis measurement target position are read:

[0009] When the axis offset is within the error range, the jacking construction proceeds normally;

[0010] When the axis offset exceeds the error range, gradually increase the oil pressure of the jacking jack corresponding to the machine head offset direction to increase the elongation value of the jacking jack until the machine head offset is adjusted to within the error range, and then gradually reduce the oil pressure of the jacking jack corresponding to the machine head offset direction to balance with other jacking jacks;

[0011] At the same time, during the jacking construction process, the upper soil layer at the front end of the jacking route is reinforced by grouting;

[0012] When the upper soil layer at the front end of the jacking route is a soft soil layer, the grouting reinforcement construction method is: use sleeve valve pipe to grout the front end of the jacking route, and the pile positions are arranged in a plum blossom shape;

[0013] When the upper soil layer at the front end of the jacking route is a garbage backfill layer, the grouting reinforcement construction method is: high-pressure rotary jet pile grouting construction, and the pile positions are arranged in a plum blossom shape;

[0014] S40: After the pipe jacking machine advances to the starting well, the construction is completed.

[0015] Preferably, in step S30, when the upper soil layer at the front end of the jacking distance is subjected to grouting reinforcement, when the depth of the upper soil layer is greater than the depth of the lower end position of the machine head, the depth of the reinforcement grouting is to below the machine head; when the depth of the upper soil layer is less than the depth of the lower end position of the machine head, the depth of the reinforcement grouting is to the top of the lower rock layer.

[0016] Preferably, the step S10 further includes predicting and calculating the pipeline side friction resistance according to the jacking length of the pipe jacking machine and the geological conditions. The theoretical calculation formula of the pipeline side friction resistance is as follows:

[0017] F2=πf k DL

[0018] Among them, F2 is the side friction resistance of the pipeline (kN); D is the outer diameter of the pipeline (m); L is the pipeline jacking length (m); fk is the average friction resistance per unit area between the outer wall of the pipeline and the soil.

[0019] Preferably, in step S30, during the jacking construction by the pipe jacking machine, it also includes synchronously injecting thixotropic mud into the space between the outer wall of the pipe and the surrounding soil to form a mud sleeve, wherein the specific gravity parameter of the thixotropic mud is determined with reference to the predicted calculated pipeline side friction resistance.

[0020] Preferably, in step S30, during the jacking construction process of the pipe jacking machine, the damage degree of the uninstalled pipe and the installed pipe are respectively detected:

[0021] If both the uninstalled pipes and the installed pipes are not damaged, the pipe jacking construction can proceed normally;

[0022] If cracks occur in the installed pipe, the pipe jacking machine will be stopped and the pipe will be replaced. After the replacement is completed, the jacking construction will continue;

[0023] If cracks appear in the installed pipe, the pipe jacking machine will be stopped, a steel liner casing will be added inside the pipe to fix it, and epoxy resin concrete will be injected to fill the gap between the steel liner casing and the pipe. After the epoxy resin concrete hardens, the pipe jacking machine will continue the jacking construction.

[0024] If the concrete of the pipe wall of an installed pipe is damaged, the pipe jacking machine will be stopped, the concrete at the damaged part of the pipe wall will be cleaned and filled with epoxy resin concrete. After the epoxy resin concrete has hardened, a steel liner casing will be added to the damaged pipe and the two adjacent pipe sections, and epoxy resin concrete will be injected into the gap between the steel liner casing and the three pipe sections. After the epoxy resin concrete has hardened, the pipe jacking machine will continue the jacking construction.

[0025] The comprehensive effects brought by the present invention include: the present invention combines specific projects to study and analyze the construction technology of pipe jacking in inhomogeneous rock formations with soft upper part and hard lower part in municipal engineering. The problem of machine head offset in soft upper part and hard lower part formations is solved by increasing the number of jacking jacks; the problem of insufficient thickness of the covering layer and machine head offset is solved by grouting and reinforcing the soil layer at the front end of the jacking route; the problem of blockage during jacking construction of garbage backfill layer is solved by predicting and calculating the side friction resistance of the pipeline before jacking construction and allocating thixotropic mud with different specific gravity parameters; the problem of pipeline damage during jacking is solved by reinforcing the pipeline, which has guiding significance for the practical application of similar projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of guide rail surveying and layout.

[0027] Figure 2 This is the relationship diagram between the jacking distance and the jacking force under different slurries.

[0028] Figure 3 This is the relationship diagram between the jacking distance and the jacking force calculation.

[0029] In the drawings, the same components are denoted by the same reference numerals; the drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0030] The present invention is further described below with reference to the accompanying drawings and embodiments.

[0031] Example

[0032] This embodiment is combined with the specific engineering construction to make a detailed description of the technical solution of the present invention. The engineering sewage pipeline is laid along the existing roads on both sides of the river for 6000m. As the main sewage collection pipeline, the sewage outlets along the way are intercepted through the interception wells, and the collected sewage is finally sent to the sewage treatment plant. Since the newly built sewage pipeline is located in the old city, one side is adjacent to the river and the other side is adjacent to the street. The space between the river and the street is narrow, and there is no condition for excavation and burial of pipes, so the construction can only be carried out by jacking. The burial depth of the jacking pipe is 2m to 8m. The geology passed through during the jacking construction is mostly silt sand in the upper layer, and the thickness of the silt sand is uneven. The local section gradually changes from the whole section of silt sand layer to the whole rock layer, and the riverside area contains a large amount of construction waste, medical waste and other wastes, and the lower layer is medium hard rock and hard rock. The jacking pipe is constructed by the mud balance method. The pipe used is a grade III concrete pipe, and the interface is a steel-bearing interface. The length of each section is 2.5m. The distance between the jacking wells is determined according to the river curve and is controlled between 40m and 160m.

[0033] Specifically, in combination with specific construction, this embodiment provides a pipe jacking construction method for a composite stratum with soft upper and hard lower layers, including:

[0034] S10. After the distance between the jacking wells is confirmed, the two adjacent jacking wells are used as the starting well and the hoisting well. After the construction is completed, guide rails and other auxiliary facilities are installed in the starting well, and the jacking machine is hoisted and lowered into the starting well for installation;

[0035] As the length of the jacking distance increases, the friction resistance on the side of the pipeline (hereinafter referred to as the pipeline side friction resistance) becomes larger and larger. The increase in pipeline side friction resistance will increase the pressure of the jacking jack hydraulic oil pump and the tonnage of the jack equipment invested. Since the pipeline is unevenly stressed during the jacking process due to geological factors and the quality of the pipeline itself varies, it is easy to cause the pipeline to rupture and affect subsequent jacking. Therefore, the jacking force must be calculated before construction to ensure that the pressure applied to the pipeline is less than the compressive strength of the pipeline concrete. In order to ensure smooth jacking, different proportions of thixotropic mud should be prepared for different strata during the construction process to reduce resistance.

[0036] Resistance calculation:

[0037] F=F1+F2

[0038] F1=πD 2 (γ g H g ) / 4

[0039] F2=πf k DL

[0040] Where, F is the jacking resistance (kN); F1 is the front resistance of the jacking machine (kN); F2 is the side friction resistance of the pipeline (kN); D is the outer diameter of the pipeline (m); L is the jacking length of the pipeline (m); f kis the average friction resistance per unit area between the outer wall of the pipe and the soil, which is 5kN / m 2 ; γ g is the density of the soil, take 18.5kN / m 3 ; Hg is the thickness of the overburden layer, which is 8m. The calculation results of the jacking force and jacking distance are shown in Table 1. Through calculation, it is found that two 250T jacks can theoretically meet the requirements. In order to prevent sudden changes in geology, four 250t jacking jacks are equipped, and the jacking jacks are evenly distributed around the circumference and set in an X shape.

[0041] Table 1 Calculation results of top distance and top force

[0042]

[0043] In addition, before the jacking construction, the jacking machine needs to be accurately measured and controlled: the control point closest to the starting well is used as the base point, and the measuring line point and level point are led to the vicinity of the working well. Three measuring points are arranged to form a closed line and leveling network. The ground coordinates and direction are transmitted to the working well by a total station, the design center line of the jacking pipe is determined, and the elevation is transmitted to the fixed point under the working well through two levels and a steel ruler. [6] The key point of accurate starting of the pipe jacking machine lies in the installation accuracy of the guide rail. The radius (outer diameter) of the pipe jacking machine is R, and the distance between the guide rails is A. Then the height difference h from the contact surface of the rail to the center of the pipe jacking machine or the height difference Rh to the bottom of the pipe can be calculated. Then the top elevation of the guide rail is calculated as = the design elevation of the bottom of the pipe + the height difference from the contact surface of the rail to the bottom of the pipe. Determine the elevation and slope of the guide rail based on the calculated data, and determine the center position of the guide rail based on the stakeout axis point, as shown in the attached figure. Figure 1 shown.

[0044] S20. Paste a shock-absorbing plate between the front end of the first section of the pipeline and the entire section of the contact surface of the pipe jacking machine. The shock-absorbing plate is made of a template or plywood with a thickness of 5 mm to reduce the impact of the vibration of the pipe jacking machine on the pipeline during the jacking process.

[0045] S30, the pipe jacking machine is connected to the first section of the pipe and then the pipe jacking machine is used for jacking construction. Steps S301, S302, S303 and S304 are parallel construction steps:

[0046] S301. During the jacking construction process, making the machine head move forward according to the designed route is the key to pipeline line control. If the conventional jacking method is used in the soft upper and hard lower strata, the machine head is prone to deviation during the jacking process. If the deviation is not corrected in time, the line deviation will be too large. After the deviation is corrected, a fold point will inevitably be formed, the friction of the pipe wall will increase, and the tongue and groove seam of the concrete pipe interface cannot be completely matched, causing the fold point to open, the force area of ​​the pipeline to decrease, and the pipe wall is prone to cracking. When the machine head is in the soft upper and hard lower soil layer and the thickness of the hard stone layer is greater than 1 / 2 of the fuselage, the machine head will rise during the jacking process. At this time, the measurement frequency should be increased, the axis measurement target position at the front machine head should be monitored, and the axis offset and offset direction of the axis measurement target position should be read:

[0047] ①When the axis offset is within the error range, the jacking construction proceeds normally;

[0048] ② When the axis offset exceeds the error range, gradually increase the oil pressure of the jacking jack corresponding to the machine head offset direction to increase the elongation value of the jacking jack, until the machine head offset is adjusted to within the error range, and then gradually reduce the oil pressure of the jacking jack corresponding to the machine head offset direction to balance with other jacking jacks;

[0049] Specifically: when the axis offset exceeds the error range and the offset is upward, that is, the head of the pipe jacking machine appears to be tilted upward, the oil pressure of the two upper jacking jacks is slowly increased to make the elongation value of the two upper jacking jacks slightly greater than the elongation value of the two lower jacking jacks, so that the head of the pipe jacking machine is slowly pressed down;

[0050] Specifically: When constructing in an area with an uneven lower rock layer, the side of the machine head is likely to rise or fall during the jacking process. If the machine head falls, increase the oil pressure of the two jacking jacks below so that the elongation value of the two jacking jacks below is slightly greater than the elongation value of the two jacking jacks above.

[0051] Specifically: When the machine head deviates laterally during the jacking process, the oil pressure of the two jacking jacks in the lateral direction is increased so that the elongation value of these two jacking jacks is slightly longer than the elongation value of the other two jacking jacks.

[0052] It should be noted that during the machine head correction and adjustment process, the jacking speed must be strictly controlled between 3mm / min and 5mm / min. The jacking length of the correction and adjustment must form a transition curve and no mutation point can be formed to ensure that the pipeline does not have quality problems such as cracking or damage.

[0053] S302. During the jacking construction process, due to the soft upper and hard lower ground characteristics of the stratum and the influence of groundwater buoyancy, the machine head is prone to tilt upward, affecting the jacking quality. It is necessary to synchronously perform grouting reinforcement on the upper soil layer at the front end of the jacking route;

[0054] ① When the upper soil layer at the front end of the jacking route is a soft soil layer, the grouting reinforcement construction method is as follows: use sleeve valve pipe to grout the front end of the jacking route, and the reinforcement depth is 500mm below the head of the jacking machine or down to the rock layer. If the upper layer of the passing section is a soft soil layer and the lower layer is a rock layer, the grouting reinforcement depth is to the rock layer; if the passing section is all soft soil layers, the grouting reinforcement depth is to 500mm below the head of the machine; the sleeve valve pipe grouting pile position is arranged in a plum blossom shape, with a spacing of 1500mm, a slurry water-cement ratio of 1:2, and a grouting pressure of 0.5MPa~1.0MPa; when encountering the edge areas on both sides of the road, the grouting pressure is controlled at 0.2MPa~0.5MPa to avoid the high pressure causing grouting outward from the dry masonry slabs and causing ground uplift;

[0055] ② The jacking route passes through a garbage backfill area. The backfill garbage is mainly domestic garbage and medical garbage. The garbage backfill time is more than 30 years. Since plastic products are not easy to rot, they are very easy to block the cutter head opening and the slurry pump pipe during the jacking process. When the slurry pump pipe is blocked during the jacking process, water needs to be added to clean the hole. The addition of a large amount of clean water makes it impossible to maintain the mud-water balance, which is easy to cause the machine head to collapse. Therefore, when a small amount of garbage blocks the cutter head, the cutter head can be opened and the garbage at the cutter head opening can be manually cleaned; when the garbage blocks the slurry pipe, the slurry pump connecting pipe can be disassembled to clean the garbage in the pipe;

[0056] When there is a lot of backfill garbage in front of the jacking and it is impossible to jack up normally, it is necessary to improve and reinforce the backfill garbage layer by using high-pressure rotary jetting piles. The high-pressure rotary jetting piles can solidify the garbage soil, and the scraper and roller of the jacking machine will grind the solidified cement slurry and garbage into small pieces, which are extracted through the mud pipe. Among them, the high-pressure rotary jetting piles can use single-liquid or double-liquid slurry. The diameter of the high-pressure rotary jetting piles is 400mm, and the construction range is 2m of the outer diameter of the pipe. If the upper layer of the passing section is a garbage backfill layer and the lower layer is a rock layer, the construction depth of the high-pressure rotary jetting piles is to the rock layer. If the passing section is entirely a garbage backfill layer, the construction depth of the high-pressure rotary jetting piles is to 500mm below the machine head, and the pile positions are arranged in a plum blossom shape with a spacing of 1200mm.

[0057] In addition, when jacking construction is carried out in garbage soil, necessary toxic gas detection must be carried out and workers inside the pipe must wear gas masks to ensure construction safety.

[0058] S303. During the jacking construction process, the pipe wall and the surrounding soil will rub against each other, increasing the jacking resistance. In order to reduce the resistance during the jacking process, it is necessary to inject thixotropic mud between the outer wall of the pipe and the surrounding soil to build a mud sleeve, and ensure that the injected thixotropic mud can evenly wrap the entire outer wall of the pipe. After analyzing the texture, 5 types of thixotropic muds were prepared for on-site use. The parameters of the thixotropic muds are shown in Table 2.

[0059] Table 2 Thixotropic mud parameters

[0060]

[0061] For silt soil, fine sand layer, rock layer, the soil layer has small porosity, and low viscosity and specific gravity of 1.01 (g / cm 3 )、1.03(g / cm 3 ) thixotropic mud, the grouting distance is controlled within 7.5m; for coarse sand and gravel formations, high viscosity and specific gravity of 1.05g / cm 3 ) thixotropic mud, the grouting distance is controlled within 5.0m; for backfill garbage soil layer, a higher viscosity and specific gravity of 1.10 (g / cm 3 )、1.15(g / cm 3 ) slurry, each section of the pipeline is grouted. The relationship between the top force and top distance of different thixotropic slurries and different geological conditions is shown in the attached figure. Figure 2 shown.

[0062] During the jacking process, the drag reduction effect of the calculated jacking force and the measured actual jacking force is compared and analyzed. The drag reduction effect of the thixotropic mud can reach more than 20% in the gravel layer and garbage backfill layer, and more than 40% in the rock, fine sand and clay layer. The relationship between the jacking distance and the jacking force is shown in the attached figure. Figure 3 shown.

[0063] S304. Due to the large changes in the strata, the concrete pipe is subjected to uneven stress in the jacking process. In particular, if the length of the steel belt at the pipe interface does not meet the requirements, the pipe will crack longitudinally and transversely. In severe cases, the pipe will break and cannot be pushed forward. Therefore, the damage degree of the pipe is also tested during the jacking construction process:

[0064] If both the uninstalled pipes and the installed pipes are not damaged, the pipe jacking construction can proceed normally;

[0065] If cracks occur in the installed pipe, the pipe jacking machine will be stopped and the pipe will be replaced. After the replacement is completed, the jacking construction will continue;

[0066] If cracks occur in the installed pipeline, that is, in the process of jacking, the pipe jacking machine will be stopped and a steel liner casing will be added inside the pipeline to fix it. The diameter of the steel liner casing is 10mm smaller than the inner diameter of the pipeline, and the thickness of the steel plate is 8mm. The steel liner casing is processed in five sections, each section is 500mm long, and is fixed and connected with bolts. Epoxy resin concrete is injected into the gap between the steel liner casing and the pipeline to fill it. After the epoxy resin concrete hardens, the pipe jacking machine will continue the jacking construction;

[0067] If the concrete on the pipe wall is damaged or falls off during the jacking process, the pipe no longer has the conditions to transmit force and the jacking can no longer continue. The pipe jacking machine must be stopped and reinforcement measures must be taken: remove the concrete from the damaged part of the pipe wall and fill it with epoxy resin concrete. After the epoxy resin concrete hardens, add a steel liner sleeve to the damaged pipe and the two adjacent pipe sections. After the three sections of steel liner sleeves are connected into a whole, epoxy resin concrete is injected into the gap between the steel liner sleeve and the three sections of the pipe. After the epoxy resin concrete hardens, the pipe jacking machine continues the jacking construction.

[0068] S40: After the pipe jacking machine advances to the starting well, the construction is completed.

[0069] The embodiment of the present invention ensures that the posture of the machine head entering the hole is consistent with the designed posture through precise initial measurement and control technology, laying the foundation for the linear control of subsequent jacking. The jacking axis measurement technology ensures that the jacking line advances according to the designed line. The technical idea of ​​using different thixotropic mud mix ratios under different geological conditions is proposed. A solution to the damage of concrete pipes during jacking, a solution to pipe blocking in the landfill section, and a technical solution for correcting deviations during jacking are proposed.

[0070] The present invention studies and analyzes the construction technology of pipe jacking in inhomogeneous rock formations with soft upper part and hard lower part in municipal engineering in combination with specific projects. The problem of machine head offset in soft upper part and hard lower part strata is solved by increasing the number of jacking jacks; the problem of insufficient thickness of the covering layer and machine head offset is solved by grouting and reinforcing the soil layer at the front end of the jacking route; the problem of blockage during jacking construction of garbage backfill layer is solved by predicting and calculating the side friction resistance of the pipeline before jacking construction and allocating thixotropic mud with different specific gravity parameters; and the problem of pipeline damage during jacking is solved by reinforcing the pipeline, which has guiding significance for the practical application of similar projects.

[0071] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0072] The present invention has been described above with reference to the preferred embodiments, but the protection scope of the present invention is not limited thereto, and all technical solutions falling within the scope of the claims are within the protection scope of the present invention. Various improvements may be made to the present invention and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A pipe jacking construction method for upper soft and lower hard composite strata, characterized in that: The construction steps include: S10, construction of the starting well and the hoisting well, the pipe jacking machine is hoisted and lowered into the starting well for installation; S20, a shock absorbing plate is pasted between the front end of the first section of the pipe and the entire section of the contact surface of the pipe jacking machine; S30, after the pipe jacking machine is connected to the pipeline, the jacking construction is carried out. During the jacking construction process, the axis measurement target position at the machine head is monitored, and the axis offset and offset direction of the axis measurement target position are read: When the axis offset is within the error range, the jacking construction proceeds normally; When the axis offset exceeds the error range, gradually increase the oil pressure of the jacking jack corresponding to the machine head offset direction to increase the elongation value of the jacking jack until the machine head offset is adjusted to within the error range, and then gradually reduce the oil pressure of the jacking jack corresponding to the machine head offset direction to balance with other jacking jacks; At the same time, during the jacking construction process, the upper soil layer at the front end of the jacking route is grouting reinforced: when the upper soil layer at the front end of the jacking route is a soft soil layer, the grouting reinforcement construction method is: use sleeve valve pipe to grout the front end of the jacking route, and the pile position is arranged in a plum blossom shape. If the upper layer of the passing section is a soft soil layer and the lower layer is a rock layer, the grouting reinforcement depth is to the rock layer; if the passing section is all soft soil layers, the grouting reinforcement depth is to 500mm below the head of the machine; when the upper soil layer at the front end of the jacking route is a garbage backfill layer The grouting reinforcement construction method is: high-pressure rotary jet pile grouting construction, and the pile positions are arranged in a plum blossom shape; high-pressure rotary jet piles can solidify the garbage soil, and the scraper and roller of the pipe jacking machine grind the solidified cement slurry and garbage into small pieces, which are extracted through the mud pipe; if the upper layer of the passing section is a garbage backfill layer and the lower layer is a rock layer, the high-pressure rotary jet pile construction depth is to the rock layer; if the passing section is entirely a garbage backfill layer, the high-pressure rotary jet pile construction depth is to 500mm below the machine head, and the pile positions are arranged in a plum blossom shape with a spacing of 1200mm; S40, after the jacking machine advances to the starting well, the construction is completed; the step S10 also includes predicting and calculating the pipeline side friction resistance according to the jacking length of the jacking machine and the geological conditions. The theoretical calculation formula of the pipeline side friction resistance is as follows: F2=πf k DL Where, F2 is the side friction of the pipeline (kN); D is the outer diameter of the pipeline (m); L is the length of the pipeline jacking (m); f k is the average friction resistance per unit area between the outer wall of the pipeline and the soil; in the step S30, when the pipe jacking machine is in jacking construction, it also includes synchronously injecting thixotropic mud to fill the space between the outer wall of the pipeline and the surrounding soil to establish a mud sleeve, wherein the specific gravity parameter of the thixotropic mud is determined with reference to the predicted calculated pipeline side friction resistance; in the step S30, during the jacking construction of the pipe jacking machine, it also includes separately detecting the damage degree of the uninstalled pipe and the installed pipe: if the uninstalled pipe and the installed pipe are both not damaged, the jacking construction of the pipe jacking machine proceeds normally; if cracks occur in the installed pipe, the pipe jacking machine is stopped, the pipe is replaced, and the jacking construction continues after the replacement is completed; if cracks occur in the installed pipe, the pipe jacking machine is stopped, a steel liner casing is added to the pipe for fixing, and epoxy resin concrete is injected into the gap between the steel liner casing and the pipe for filling, and the pipe jacking machine continues the jacking construction after the epoxy resin concrete hardens. If the concrete of the pipe wall of an installed pipe is damaged, the pipe jacking machine will be stopped, the concrete at the damaged part of the pipe wall will be cleaned and filled with epoxy resin concrete. After the epoxy resin concrete has hardened, a steel liner casing will be added to the damaged pipe and the two adjacent pipe sections, and epoxy resin concrete will be injected into the gap between the steel liner casing and the three pipe sections. After the epoxy resin concrete has hardened, the pipe jacking machine will continue the jacking construction.

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