A composite support construction method for shield close underpassing of a sewage pipe

Abstract

The application discloses a composite support construction method for shield close-range underpassing of a sewage pipe, adopts a water guide cut-off, active protection, advanced support and dynamic regulation mode for shield tunneling, and solves the technical problem of safe shield crossing of a high-risk pipeline. Through the effective protection of the composite collaborative support system of active protection-advanced support-dynamic balance on the soil body, the displacement of the soil body around the sewage pipe in the shield tunneling process is ensured to be less than 5mm, the soil body displacement is reduced by more than 50%, and the settlement of the sewage pipe is controlled to be within 3mm, so that the risk of deformation dislocation damage of the sewage pipe caused by stratum disturbance is effectively avoided, and the safety of the tunneling construction when crossing the high-risk pipeline is significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shield construction, in particular to a composite support construction method for shield close-range underpassing of a sewage pipe. BACKGROUND

[0002] In recent years, with the continuous expansion of urban underground space development, shield tunnel underpassing of existing pipelines is facing increasingly complex technical challenges. Especially in special working conditions such as water-rich soft soil stratum and high-density built-up areas, how to effectively control stratum disturbance and ensure the safe operation of existing pipelines has become a difficult problem that the industry needs to solve. In the prior art, although the conventional pipe shed support and grouting reinforcement processes can play a certain protective role, when facing large-diameter socketed gravity sewage pipes and high-sensitivity water transmission pipelines with special structures, there are still technical bottlenecks such as insufficient control precision of stratum settlement and high risk of damage to the sealing of pipeline joints. The present application provides a composite support construction method for shield close-range underpassing of a sewage pipe to solve the above problems. SUMMARY

[0003] The present application provides a composite support construction method for shield close-range underpassing of a sewage pipe, which uses a composite collaborative support system to protect the soil during shield tunneling and accurately control the settlement of the sewage pipe.

[0004] The technical solution adopted by the present application to solve the above technical problems is as follows:

[0005] A composite support construction method for shield close-range underpassing of a sewage pipe, comprising the following steps,

[0006] S1, flow interception: determining the distribution of the sewage pipe and determining the interception point, laying a water guide pipe on the ground first, then blocking and intercepting the sewage pipe, and guiding the sewage through the water guide pipe;

[0007] S2, pipe body strengthening: after the sewage pipe is blocked and intercepted, the inside of the sewage pipe is cleaned, and then a light-curing hose is arranged in the interception solidification section of the sewage pipe to strengthen the structure of the sewage pipe;

[0008] S3, advanced support: in the range of the interception solidification section of the sewage pipe, an advanced support structure is formed by a pipe shed in the soil below the sewage pipe to reinforce the soil below the sewage pipe;

[0009] S4, shield launching: when the shield machine starts to tunnel, a steel sleeve is used to realize shield launching and to establish the soil chamber pressure in advance;

[0010] S5, underpassing pipeline: when the shield tunnels under the sewage pipe, air pressure assisted pressure maintenance and grouting consolidation operations are used to ensure the stability of the soil;

[0011] S6, restore the pipeline flow: after the shield tunneling through the sewer pipe, the sewer pipe is restored to flow through the solidification section, and then the subsequent construction of the shield tunnel is carried out.

[0012] Further, in step S1, the specific operation of cutting off the water is as follows,

[0013] S11, laying the water guide pipe: determining the distribution of the sewer pipe and counting the flow of the sewer pipe, and designing the water guide scheme of the water guide pipe;

[0014] Determine the upper and lower cutoff points of the sewer pipe, lay the water guide pipe, and connect the upper and lower ends of the water guide pipe to the upper and lower cutoff points of the sewer pipe respectively;

[0015] S12, plugging the pipeline: enter the sewer pipe through the inspection well, place the air bag in the sewer pipe and inflate it, and the air bag inflates and expands to block the sewer pipe;

[0016] S13, sewage diversion: after the sewer pipe is completely blocked, water is pumped through the water pump arranged at the upper cutoff point, and the sewage is diverted through the water guide pipe to the lower cutoff point, realizing the cutoff and water guide of the sewer pipe.

[0017] Further, in step S2, the specific operation of pipe body strengthening is as follows,

[0018] S21, pipeline cleaning: ventilating and dredging the solidification section of the sewer pipe;

[0019] S22, soft tube filling: first lay the bottom film, then put the front end of the light curing soft tube into the sewer pipe, pull the front end of the light curing soft tube into the sewer pipe, until the two ends of the light curing soft tube respectively extend out of the solidification section of the sewer pipe, then close one end of the light curing soft tube, inflate the light curing soft tube from the other end, so that it fully expands and completely adheres to the inner wall of the sewer pipe, and the soft tube is preliminarily shaped after pressure maintaining for a period of time;

[0020] S23, soft tube curing: put the ultraviolet curing equipment into the shaped light curing soft tube, and move the ultraviolet curing equipment in the light curing soft tube to cure the light curing soft tube;

[0021] When the ultraviolet light is cured, a plurality of ultraviolet light curing devices are arranged before and after the preheating, main curing and post-curing operations;

[0022] S24, trimming and cleaning: after the light curing soft tube is cured, the overhanging section of the light curing soft tube is cut off and trimmed, and then the laid bottom film is pulled out, at this time the sewer pipe is structurally reinforced by the cured light curing soft tube.

[0023] Further, in step S3, the specific operation of the advance support is: drilling a hole in the soil between the sewer pipe and the shield tunnel, during the drilling operation, the hole axis is parallel to the shield tunnel axis, and the hole is located above the shield tunnel, then a steel pipe is inserted into the hole, and then the hole is grouted to form a pipe shed, and the plane formed by the pipe shed is parallel to the sewer pipe.

[0024] Further, in step S4, the specific operation of the shield launching is: assembling the shield machine and the steel sleeve, when the shield machine advances to the portal position, inert slurry is injected into the steel sleeve, the air compressor of the shield machine is started to establish the soil chamber pressure, when the design pressure balanced with the stratum is reached, the shield machine starts to excavate, and the synchronous mortar is injected while the shield machine excavates to fill the gap between the segment and the steel sleeve, and the shield machine excavates to the whole into the stratum and maintains the soil chamber pressure value.

[0025] Further, in step S5, the specific operation of the air pressure assisted pressure maintaining and grouting consolidation during the shield machine excavation is as follows:

[0026] S51, air pressure assisted pressure maintaining: low position air pressure is used to assist the shield machine excavation to make the soil chamber pressure within the pressure maintaining range, and the shield machine excavation speed is controlled to make it pass through the sewer pipe segment quickly and uniformly;

[0027] S52, grouting consolidation: synchronous grouting is used when the shield machine excavates through the sewer pipe, and when the shield machine excavates directly below the sewer pipe, the center of the sewer pipe is taken as the center, the front and rear segments are grouted with quick-setting synchronous grouting, the above segments are consolidated into a whole segment group, and then the front and rear segments of the whole segment group are filled with double-liquid slurry secondary grouting to fill the vault stratum, and the whole segment group is pulled and fixed by the front and rear segments to avoid the whole segment group floating up.

[0028] Further, in step S52, the setting time of the synchronous grouting is 3-5h, and the setting time of the quick-setting synchronous grouting is 2h.

[0029] Further, in step S5, the soil displacement monitoring is carried out during the shield machine excavates through the sewer pipe, the monitoring steel bars are arranged at the positions corresponding to the sewer pipe directly below and the front and rear two segments, the steel bars are vertically inserted into the soil by 3m, and the top end is exposed on the ground by 10mm.

[0030] Further, the intercepting and solidifying section of the sewer pipe includes an intercepting section and a solidifying section, the sewer pipe above the shield tunnel is the solidifying section, the inspection well is the boundary, the intercepting section is located on both sides of the solidifying section, and the end of the solidifying section extends outward by one inspection well to form the intercepting section.

[0031] Further, double air bags are arranged in the intercepting section of the sewer pipe, two air bags are arranged in each intercepting section, and the two air bags are arranged at the two ends of the intercepting section.

[0032] The present application has the following advantages:

[0033] The effective protection of the soil by the composite collaborative support system of active protection-advance support-dynamic balance ensures that the displacement of the soil around the sewage pipe during shield tunneling is less than 5mm, the soil displacement is reduced by more than 50%, and the settlement of the sewage pipe is controlled within 3mm, effectively avoiding the risk of deformation and misplacement damage of the sewage pipe caused by stratum disturbance, and significantly improving the safety of tunneling construction when crossing high-risk pipelines;

[0034] The composite support system formed by ultraviolet curing of the sewage pipe and advance pipe shed support in the underlying soil effectively controls the stratum deformation, significantly reduces the deformation and displacement of the sewage pipe caused by shield tunneling, and realizes the inhibition of stratum disturbance and the protection of pipeline sealing;

[0035] The collaborative control of soil pressure-grouting parameters-tunneling speed is adopted during shield tunneling to realize accurate control of soil pressure, and through the dynamic filling optimization of quick-setting synchronous mortar and secondary grouting, a three-dimensional support system of "front and rear pull connection and middle support" is formed, which realizes active control of the attitude of the pipe segment and stratum deformation, avoids the influence of the attitude of the pipe segment on the stratum, and further reduces the influence of stratum disturbance on the pipeline. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall construction state of the present application;

[0037] Figure 2 It is a schematic diagram of the position state of the tunnel and the sewage pipe of the present application;

[0038] Figure 3 It is a schematic diagram of the shield tunneling state of the present application;

[0039] Figure 4 It is a schematic diagram of the starting state of the shield tunneling machine of the present application.

[0040] The drawings show that: 1, sewage pipe; 101, trapped section; 102, cured section; 2, water guide pipe; 3, air bag; 4, light curing hose; 5, pipe shed; 6, shield tunnel; 7, shield tunneling machine; 8, steel sleeve; 9, integral pipe segment group. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings of the specification. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0042] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0043] like Figure 1 As shown, a specific embodiment of the present invention is the construction of a central station in a certain place, and a D1200 socket-type reinforced concrete sewage main is laid horizontally under the main road in the station tunnel. The sewage pipe is constructed using the jacking method, with a single-section pipe length of 2~3m and a pipe bottom buried at a depth of 6.6m. The average daily sewage flow is 20,000~30,000 m³. The tunnel construction shield uses a φ8840mm earth pressure / mud-water dual-mode shield machine, which uses the earth pressure mode for excavation. The length of the underpass section is 38.4m, and the vertical net distance from the sewage pipe is only 2.591m. The upper part of the arch of the shield underpass section is <4N-2> plastic silty clay, and the base of the sewage pipe is located in this soil layer; the stratum through which the heading passes is <6> Fully weathered muddy siltstone, <7-3> strongly weathered muddy siltstone and <8-3> moderately weathered muddy siltstone, the above geological conditions are prone to soil disturbance and water loss and settlement risks during shield tunneling. During the construction process, since the sewage pipe is connected with an F-shaped steel socket, the rubber ring seal allows only 5mm of deformation. Therefore, during shield tunneling, the stratum deformation control accuracy needs to be ≤5mm. Due to the complex terrain and pipelines and special geological conditions, it is difficult to control the stratum deformation within 5mm during shield tunneling. The active protection-advance support-dynamic balance composite collaborative support system adopted by the present invention effectively protects the soil, ensures that the displacement of the soil around the sewage pipe during shield tunneling is less than 5mm, and controls the settlement of the sewage pipe within 3mm, effectively avoiding the risk of deformation, dislocation and damage of the sewage pipe due to stratum disturbance, and significantly improving the safety of tunneling construction when crossing high-risk pipelines.

[0044] like Figure 1 、 2As shown, the composite support construction method for shield close-range underpassing of sewage pipes of the present application realizes shield tunneling underpassing of sewage pipes by adopting the steps of water diversion and interception, active protection, advanced support and dynamic regulation, and solves the technical problem of safe shield underpassing of high-risk pipelines. In order to enhance the deformation resistance of the sewage pipes, a photocured hose is arranged in the sewage pipe to strengthen the structure of the sewage pipe, the photocured hose in the sewage pipe can effectively enhance the structural strength of the sewage pipe, and at the same time, the sewage pipes are integrated, the deformation resistance of the adjacent sewage pipe joints is enhanced, a pipe shed is arranged in the soil between the sewage pipe and the shield tunnel to form an advanced support structure, the disturbance to the soil during shield tunneling is reduced, the displacement and deformation of the sewage pipe caused by soil disturbance are avoided, and the influence of the deformation of the soil itself on the sewage pipe during shield tunneling is effectively reduced by the joint cooperation of active protection and advanced support; during shield tunneling, the soil chamber pressure, grouting parameters and tunneling speed are cooperatively controlled to ensure the dynamic balance during tunneling, thereby reducing the disturbance to the soil and ensuring the stability of the soil, which reduces the influence of the soil on the sewage pipe, and the displacement of the sewage pipe is controlled within the design range.

[0045] As shown in Figure 1 S1, water diversion and interception: determine the distribution of the sewage pipe 1, determine the interception point, lay the water diversion pipe 2 on the ground first, then block and intercept the sewage pipe 1, and guide the sewage through the water diversion pipe 2.

[0046] The specific operation of water diversion and interception is as follows:

[0047] S11, laying the water diversion pipe: according to the sewage pipe completion drawing and the actual measured data of sewage flow, the current use of the φ1200 sewage main pipe and the maximum sewage flow of 20000-30000 m³ during peak period are determined, the diameter, number and sewage pump model of the diversion pipe are calculated according to the daily flow, and then the two branch pipes in the sewage pipe repair section are determined, which are φ500 HDPE sewage pipe and φ1200 sewage concrete pipe.

[0048] The specific operation of water diversion and interception is as follows:

[0049] The φ1200 sewage main pipe adopts three 1000 m³ / h sewage pumps, one of which is used and one is reserved, and three φ300 PE pipes and φ300 fire hoses are configured as water diversion equipment; the φ1200 sewage branch pipe adopts two 1000 m³ / h sewage pumps, one of which is used and one is reserved, and two φ300 PE pipes and φ300 fire hoses are configured as water diversion equipment.

[0050] Calculation of the maximum flow of the φ1200 sewage main pipe:

[0051] According to the upper limit of daily flow of 30000 m³ / d, the hourly flow is:

[0052] 30000 / 24=1250 m³ / h;

[0053] The flow capacity of the water conduit 2 is calculated as follows:

[0054] The cross-sectional area of a single φ300 PE pipe is A=π×0.3² / 4≈0.0707㎡,

[0055] Taking a reasonable flow rate of 1.5 m / s, the flow rate of a single pipe is Qsingle pipe=0.0707×1.5×3600s / h≈381.6m³ / h,

[0056] The total flow capacity of two PE pipes is 381.6m³ / h×2=763.2 m³ / h,

[0057] The flow capacity of two water pumps is calculated as follows: the rated flow rate of a pump is 1000 m³ / h;

[0058] The total flow capacity is 763.2 m³ / h +1000×2=2763.2 m³ / h;

[0059] The flow capacity of the above flow diversion scheme is 2763.2 m³ / h, which exceeds the daily average maximum flow rate of 1250 m³ / h, meeting the flow diversion requirements.

[0060] The upper and lower interception points of the sewage pipe 1 are determined, and the water conduit 2 is laid on the road surface, and then the upper and lower ends of the water conduit 2 are connected to the upper and lower interception points of the sewage pipe 1 respectively by breaking the road surface.

[0061] As shown in FIG. 12, S12, after the water conduit 2 is arranged, the air bag 3 is placed in the sewage pipe through the inspection well and inflated, and the air bag 3 is inflated to block the sewage pipe; Figure 2 The blocking and interception are performed by using double air bags to block synchronously. Two air bags 3 are arranged in each interception section of the sewage pipe, and two air bags 3 with the same inner diameter as the pipe are arranged in each interception section. The two air bags 3 are arranged at the two ends of the interception section, i.e., two air bags 3 are arranged at the two ends of the interception section of the sewage pipe, and a total of four air bags 3 are arranged. Among the two air bags 3 at each end, the first air bag 3 is arranged at the interception point, and the second air bag 3 is arranged at a position moving inward by one inspection well. The double air bags are used to ensure the blocking effect.

[0062] The inflation pressure of the air bag 3 is 80% of the design value, i.e., 0.12 MPa. After pressure maintenance for 30 min, the pressure drop is ≤5%, proving the sealing property.

[0063]

[0064] ​S13, sewage diversion: After the sewage pipe 1 is completely blocked, water is pumped out by a water pump located at the upper interception point, and the sewage is diverted to the lower interception point through the water guide pipe 2, thereby intercepting and diverting the sewage pipe 1, making the sewage pipe 1 a waterless environment.

[0065] Through the above operations, water is diverted and intercepted from the sewage pipe above the shield tunnel, creating a water-free environment inside the sewage pipe, which makes it easier to use active protection measures such as light curing in the sewage pipe to strengthen the pipe body and avoid affecting the pipe body during shield construction.

[0066] like Figure 2 As shown, S2, pipe body reinforcement: after the sewage pipe 1 is blocked and intercepted, the interior of the sewage pipe 1 is cleaned, and then a light-curing hose 4 is set in the interception and curing section of the sewage pipe 1 to strengthen the sewage pipe structure.

[0067] The interception and solidification section of the sewage pipe 1 includes an interception section 101 and a solidification section 102. The sewage pipe above the shield tunnel is the solidification section 102. The solidification section 102 is structurally reinforced by a light-curing hose 4 to ensure the safety and stability of the sewage pipe 1 during shield excavation. The interception section 101 is located on the front and rear sides of the solidification section 102 with the inspection well as the boundary. The end of the solidification section 102 extends outward by an inspection well as the interception section 101. An air bag 3 is provided in the interception section 101, and the sewage pipe 1 is sealed and intercepted by the air bag 3 to ensure that the solidification section 102 is in a water-free environment.

[0068] The specific operations of pipe strengthening are as follows:

[0069] S21, pipeline cleaning: ventilating and desilting the solidified section 102 of the sewage pipe 1;

[0070] The curing section 102 of the sewage pipe 1 is 79m long. Forced ventilation is first performed, and then high-pressure water is used to flush and break the hard protrusions to ensure that the inner wall of the pipe is clean and smooth, thereby ensuring that the light-curing hose 4 effectively fits the inner wall of the sewage pipe 1.

[0071] S22, hose filling: first lay the base film, then place the front end of the light-curing hose 4 made of glass fiber hose into the sewage pipe 1, pull the front end of the light-curing hose 4 into the sewage pipe 1 until both ends of the light-curing hose 4 extend out of the curing section 102 of the sewage pipe 1, then seal one end of the light-curing hose 4, and inflate the light-curing hose 4 from the other end to 0.05-0.1 MPa to allow it to fully expand and completely fit against the inner wall of the sewage pipe 1. Maintain the pressure for 20-40 minutes to allow the light-curing hose 4 to take initial shape and completely fit against the inner wall of the sewage pipe 1.

[0072] S23, hose curing: open the inflation port, put the ultraviolet curing equipment into the inflatable and shaped light-cured hose 4, and move the ultraviolet curing equipment in the light-cured hose 4 at a speed of 0.2-0.3 m / min, so as to uniformly cure the light-cured hose 4;

[0073] During ultraviolet curing, four-zone step temperature control is adopted, four groups of ultraviolet curing equipment are arranged according to the operation of preheating, main curing and post-curing, one group of ultraviolet curing equipment is arranged in the preheating zone, the temperature is controlled at 51-61℃, which plays a role in softening the resin, two groups of ultraviolet curing equipment are arranged in the main curing zone, the temperature is controlled at 69-74℃ and 78-83℃, which plays a role in exciting the photoinitiator, one group of ultraviolet curing equipment is arranged in the post-curing zone, the temperature is controlled at 39-42℃, which plays a role in stabilizing the molecular structure, and the overall curing temperature is controlled at 80-130℃.

[0074] S24, trimming and cleaning: after the light-cured hose 4 is cured and cooled to room temperature, the overhanging section at the end of the light-cured hose 4 is cut and trimmed, then the laid bottom film is pulled out, and epoxy resin is used to fill the gap between the light-cured hose 4 and the sewage pipe 1, at this time the sewage pipe 1 is reinforced by the cured light-cured hose 4, the thickness of the cured light-cured hose 4 is 8 mm, the shear strength is ≥18 MPa, and the bending strength is ≥80 MPa.

[0075] The active protection means of light curing is used to reinforce the pipe body of the sewage pipe 1, so that when the soil outside the sewage pipe 1 deforms, the light-cured hose 4 on the inside supports it, avoiding deformation or misplacement of the pipe body, thereby improving the anti-deformation ability of the pipe body.

[0076] As shown in Figure 2 S3, advance support: in the range of the interception and curing section of the sewage pipe 1, a pipe shed 5 is formed in the soil below the sewage pipe 1 to form an advance support structure, and the soil below the sewage pipe 1 is reinforced;

[0077] The pipe shed 5 is composed of steel pipes with their axes parallel to the axis of the shield tunnel, a plurality of φ108 steel pipes are arranged at intervals of 500 mm to form the pipe shed 5, and the plane formed by the pipe shed 5 is parallel to the sewage pipe 1, the steel pipes are arranged perpendicular to the sewage pipe 1 and their ends exceed the sewage pipe 4030 mm, forming an advance support between the sewage pipe 1 and the shield tunnel 6, and forming a continuous rigid support barrier.

[0078] As shown in Figure 2 , 3The specific operation of the advance support is shown in the figure: a φ120 drill bit is used to drill a hole in the soil between the sewage pipe 1 and the shield tunnel 6. During the drilling operation, the hole axis is parallel to the shield tunnel 6 axis, and the hole is located above the shield tunnel 6. The drilling depth is 30 m, the drilling end exceeds the sewage pipe 4030 mm, then a φ108 steel pipe is inserted into the hole and pushed to the designed depth, then the hole is grouted to form a pipe shed 5. During grouting, cement slurry is used, the water-cement ratio is 1:1, and the pressure is controlled at 0.6-0.8 MPa.

[0079] The active protection of the sewage pipe 1 by the light-cured hose 4 and the advance support of the soil by the pipe shed 5 work together to effectively control the ground deformation and significantly reduce the influence of soil deformation on the sewage pipe 1, achieving the inhibition of ground disturbance and the protection of the pipeline.

[0080] As shown in the figure, Figure 4 S4, shield launching: when the shield machine 7 starts to excavate, a steel sleeve 8 is used to realize shield launching and establish the soil chamber pressure in advance.

[0081] The specific operation of shield launching is as follows: first, the steel sleeve 8 base is hoisted into the well in 4 blocks, connected with M30 high-strength bolts and steel sleeve flange plate, and sealed with 8mm rubber pads at the flange joint. After the shield main machine is hoisted into the well and positioned, the upper cover part of the steel sleeve and the reaction frame are assembled, φ609 steel pipe diagonal bracing and 30# channel steel reinforcement are set, and the assembly of the shield machine 7 and the steel sleeve 8 is completed.

[0082] When the shield machine 7 advances to the portal position, inert slurry is injected into the steel sleeve 8, the injection port is sealed after filling, the shield machine 7 is started synchronously to establish the soil chamber pressure, and when the design pressure balance with the ground is reached, the shield machine 7 starts to excavate. While the shield machine 7 excavates, the segments are assembled at the shield tail and synchronous mortar is injected into the steel sleeve 8 to fill the gap between the segments and the steel sleeve 8. The shield machine 7 excavates to the whole into the soil, and maintains the set pressure value of the soil chamber.

[0083] S5, underpass pipeline: when the shield excavates under the sewage pipe 1, air pressure assisted pressure maintenance and grouting consolidation operation are used to ensure soil stability.

[0084] The specific operation of the air pressure assisted pressure maintenance and grouting consolidation used by the shield machine 7 during excavation is as follows:

[0085] S51, air pressure auxiliary pressure maintaining: the shield machine 7 adopts low bin position air pressure auxiliary when tunneling to make the soil bin pressure in the pressure maintaining range, the shield tunneling adopts low bin position tunneling mode, the muck covers the top of the front gate in front of the screw machine, the remaining soil bin volume is filled by 2 sets of 2x15 m3 / min air compressors, and an automatic pressure maintaining system is configured, the pressure is monitored in real time through the sensor arranged at the top of the soil bin, so that the soil bin pressure is maintained at the design pressure 1.0 bar; the tunneling speed of the shield machine 7 is controlled at 37-40 mm / min, so that it quickly and uniformly passes through the sewage pipe section, and the bentonite thick slurry is injected from the front and middle shield radial holes at the same time when tunneling, the single ring injection amount is about 3 m3, so that the thick slurry fills the full weathered rock fissures, closes the groundwater seepage path, and supports the arch top stratum.

[0086] Selection of the soil bin pressure value P:

[0087] P=Pw+Pr

[0088] In the formula: P is the preset standard pressure value of the soil bin;

[0089] Pw is the water head pressure calculated to the tunnel top,

[0090] Pw=103Kg / m3 (density of water) x 9.8N / Kg (gravity of the object) x m (buried depth);

[0091] Pr is the soil pressure, which is generally set to be higher than the design value by 0.2 bar;

[0092] In the embodiment, the shield tunnel underpasses the lowest point to the tunnel top buried depth of about 9.6 m, the water head pressure is 0.96 bar, the soil pressure is 0.2 bar, and the design pressure value of the automatic pressure maintaining system of the soil bin is selected as 1.0 bar according to the formula.

[0093] S52, grouting consolidation: the shield machine 7 adopts synchronous grouting when tunneling, and the injection amount is about 11 m3; when synchronous grouting, the setting time is 3-5 h;

[0094] The grouting amount calculation formula of synchronous grouting: Q=π×(D²-d²) / 4×L×λ;

[0095] The diameter of the shield cutterhead D=8840mm=8.84m,

[0096] The outer diameter of the segment d=8500mm=8.5m,

[0097] The segment length L=1600m=1.6m,

[0098] The injection rate λ=120-150%,

[0099] The calculated theoretical void volume is: 4.63 m3x1.6≈7.41 m3,

[0100] Consider the injection rate: 7.41 m³ x 140% = 10.374 m;

[0101] When the shield machine 7 excavates to the sewage pipe directly below, the 17th segment of the sewage pipe directly below is taken as the center, and the front and rear 5 segments of the pipe segment are filled with quick-setting synchronous grouting. The above-mentioned 10 segments of pipe segments are consolidated into an integral pipe segment group 9. When the integral pipe segment group is filled with quick-setting synchronous grouting, the setting time is 2h; Specifically, when the synchronous mortar tank of the shield trolley is filled with synchronous mortar, the synchronous mortar mixture ratio is first adjusted to the initial setting time of 3-5h, and when the shield machine excavates to the sewage pipe below, the synchronous mortar tank of the shield trolley is filled with a setting agent, 3kg of setting agent powder per m³ of synchronous mortar, and the synchronous mortar filling injection rate is adjusted to 150%, so that the synchronous mortar setting time is controlled within 2h.

[0102] As shown in Figure 3 To control the pipe segment floating, and to prevent the risk of sewage pipe uplift caused by secondary grouting pressure, no secondary double-liquid grouting is performed within the range of the integral pipe segment group 9, but the synchronous mortar is relied on to control the vault settlement, and the double-liquid grouting is performed on the front and rear 5 segments of the pipe segment outside the integral pipe segment group 9 to fill the vault stratum, and the front and rear pipe segments are used to pull and fix the integral pipe segment group 9, so as to control the pipe segment floating amount and avoid the integral pipe segment group floating.

[0103] The above-mentioned measures can effectively reduce the pipe settlement and reduce the influence on the pipe segment posture, but it is still necessary to monitor the soil displacement and pipe segment posture during the shield machine passing through the sewage pipe, and the soil displacement and pipe segment posture during the shield excavation process shall meet the design requirements.

[0104] The specific measure of soil displacement is to set monitoring steel bars at the corresponding positions of the pipe segment directly below the sewage pipe, and the front and rear two pipe segments thereof, and each group is provided with three monitoring steel bars. The steel bars are vertically inserted into the soil by 3m, and the top end is exposed on the ground by 10mm, and a protective shell is fixed. The principle is that after the steel bars are inserted into the soil, they are integrated with the soil, and when the soil deforms, the steel bars also deform correspondingly. The displacement of the monitoring steel bars can be obtained. The monitoring result is that the soil displacement shows a settlement trend before the shield passes through the sewage pipe, and the maximum settlement is-1.62mm. After the shield passes through, the soil displacement begins to show an upward trend. After the grouting consolidation method of "front and rear pull and middle support" is adopted, the maximum vertical displacement of the deep soil is 4.76mm, which meets the design requirement of soil displacement <5mm.

[0105] The specific measure for the segment posture is to use a total station instrument and an aluminum alloy ruler with a reflective sheet, to observe the segment posture, wherein the total station instrument is placed at a proper position near the center line of the shield tunnel, and each monitoring point mark and a rear view point on different sections are directly observed to obtain the spatial three-dimensional coordinates of each monitoring point in an arbitrary station center coordinate system, and the relative position relationship between each monitoring point on the same section is indirectly calculated by using the spatial three-dimensional coordinates of each monitoring point. The monitoring result is that the maximum upward displacement of the segment is 19 mm, which meets the requirement of the elevation through measurement limit difference of 50 mm in the specification.

[0106] S6, restoring the pipeline flow: after the shield tunneling machine 7 tunnels through the sewer pipe 1, the sewer pipe 1 is restored to flow through the solidification section, and then the subsequent construction of the shield tunnel is carried out.

[0107] The present application constructs a rigid protection barrier for the sewer pipeline through the synergistic effect of the ultraviolet light curing active protective layer and the advanced pipe shed support, significantly reduces the deformation influence of the shield tunneling on the socket type sewer pipe; the monitoring data shows that the maximum vertical displacement of the deep soil body around the sewer pipe is 4.76 mm, and the segment upward displacement is less than or equal to 19 mm, which proves the dual effectiveness of the above-mentioned measures for inhibiting stratum disturbance, strengthening and sealing the pipeline. Secondly, the soil chamber pressure, grouting parameters and tunneling speed are synergistically controlled, the soil pressure is maintained at the design pressure of 1 bar through air pressure assistance, and a three-dimensional support system of "front and rear pull connection and middle support" is formed through the dynamic filling optimization of fast-setting synchronous mortar and secondary grouting, thereby realizing the active control of the segment posture and stratum deformation.

[0108] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments, but that the application can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Thus, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than by the above description, and it is therefore intended that all changes and modifications that come within the meaning and range of equivalency of the claims are resolvable thereunder. Any reference signs in the claims should not be construed as limiting the claims to the figures in which the reference signs are used.

Claims

1. A composite support construction method for a shield machine passing under a sewage pipe at close range, characterized by: The following steps are included: S1, interception and diversion: Determine the distribution of sewage pipes and the interception points, first lay water pipes on the ground, then block and intercept the sewage pipes, and divert the sewage through the water pipes; S2, pipe strengthening: After the sewage pipe is blocked and intercepted, the interior of the sewage pipe is cleaned, and then a light-curing hose is installed in the interception and curing section of the sewage pipe to strengthen the sewage pipe structure; S3, advanced support: within the interception and solidification section of the sewage pipe, a pipe shed is used to form an advanced support structure in the soil below it to reinforce the soil below the sewage pipe; S4, shield start: When the shield machine starts excavation, a steel sleeve is used to start the shield and build up soil pressure in advance; S5, Underpass: When the shield tunneling reaches below the sewage pipe, air pressure-assisted pressure maintenance and grouting consolidation operations are used to ensure soil stability; S6, restore pipeline flow: After the shield machine excavates through the sewage pipe, the intercepted and solidified section of the sewage pipe is restored to flow, and then subsequent construction of the shield tunnel is carried out.

2. The composite support construction method for a shield machine passing under a sewage pipe at close range according to claim 1 is characterized in that: In step S1, the specific operation of intercepting and diverting water is as follows: S11, laying aqueducts: determine the distribution of sewage pipes and calculate the flow rate of sewage pipes, and design the aqueduct diversion plan accordingly; Determine the upper and lower interception points of the sewage pipe, lay the water pipe, and connect the upper and lower ends of the water pipe to the upper and lower interception points of the sewage pipe respectively; S12, blocking the pipe: Enter the sewage pipe through the inspection well, place an air bag in the sewage pipe and inflate it. After the air bag is inflated, it blocks the sewage pipe and intercepts the flow; S13, sewage diversion: After the sewage pipe is completely blocked, water is pumped out by a water pump installed at the upper interception point, and the sewage is diverted to the lower interception point through the water diversion pipe to achieve interception and diversion of the sewage pipe.

3. The composite support construction method for a shield machine passing under a sewage pipe at close range according to claim 1 is characterized in that: In step S2, the specific operation of tube strengthening is as follows: S21, pipe cleaning: ventilate and desilt the solidified section of the sewage pipe; S22, Hose Filling: First, lay the base film, then place the front end of the light-curing hose into the sewage pipe, pull the front end of the light-curing hose into the sewage pipe until both ends of the light-curing hose extend out of the curing section of the sewage pipe, then seal one end of the light-curing hose, and inflate the light-curing hose from the other end until it fully expands and completely fits the inner wall of the sewage pipe. Maintain pressure for a period of time to allow the hose to initially take shape. S23, tube curing: placing the UV curing device into the shaped light curing tube, and moving the UV curing device in the light curing tube to UV cure the light curing tube; During UV curing, multiple groups of UV curing equipment are set up before and after the operations of preheating, main curing, and post-curing; S24, trimming and cleaning: After the light-curing hose is cured, the protruding section at the end of the light-curing hose is cut off and trimmed, and then the laid base film is pulled out. At this time, the sewage pipe is structurally reinforced by the cured light-curing hose.

4. The composite support construction method for a shield machine passing under a sewage pipe at close range according to claim 1 is characterized in that: In step S3, the specific operation of advanced support is: drilling a hole in the soil between the sewage pipe and the shield tunnel. During the drilling operation, the axis of the hole is parallel to the axis of the shield tunnel, and the hole is located above the shield tunnel. Then, a steel pipe is inserted into the hole, and then the hole is grouting and filled to form a pipe roof. The plane formed by the pipe roof is parallel to the sewage pipe.

5. The composite support construction method for a shield tunnel under a sewage pipe at close range according to claim 1 is characterized by: In step S4, the specific operations of the shield machine are as follows: assembling the shield machine and the steel sleeve, injecting inert slurry into the steel sleeve when the shield machine advances to the portal position, and synchronously starting the air compressor of the shield machine to establish the soil bin pressure. When the design pressure is balanced with the stratum, the shield machine starts to advance. While the shield machine is advancing, synchronous mortar is injected to fill the gap between the pipe segment and the steel sleeve. The shield machine advances until it enters the soil layer as a whole and maintains the set pressure value of the soil bin.

6. The composite support construction method for a shield machine passing under a sewage pipe at close range according to claim 1 is characterized in that: In step S5, the specific operations of air pressure-assisted pressure maintenance and grouting consolidation used during shield machine excavation are as follows: S51, air pressure assisted pressure maintenance: When the shield machine is excavating, low-level air pressure is used to assist the soil bin pressure to keep it within the pressure maintenance range, and the shield machine's excavation speed is controlled so that it passes through the sewage pipe section quickly and evenly; S52, grouting consolidation: Synchronous grouting is used when the shield machine excavates through the sewage pipe. When the shield machine excavates to the bottom of the sewage pipe, rapid-setting synchronous grouting is used for multiple segments in front and behind it, with the bottom of the sewage pipe as the center, to consolidate the above segments into an integral segment group. Then, double-liquid slurry is used for secondary grouting of multiple segments in front and behind the integral segment group to fill the vault stratum. The segments in front and behind are used to tighten the integral segment group to prevent the integral segment group from floating up.

7. The composite support construction method for a shield machine passing under a sewage pipe at close range according to claim 6 is characterized by: In step S52, when synchronous grouting is performed, the setting time is 3-5 hours, and when rapid setting synchronous grouting is performed, the setting time is 2 hours.

8. The composite support construction method for a shield machine passing under a sewage pipe at close range according to claim 1 is characterized by: In step S5, soil displacement monitoring is performed while the shield machine passes through the sewage pipe. Monitoring steel bars are set at the corresponding positions of the pipe segment directly below the sewage pipe, two pipe segments in front of it, and two pipe segments behind it. The steel bars are vertically inserted into the soil for 3m, and the top is exposed 10mm above the ground.

9. The composite support construction method for a shield machine under a sewage pipe at close range according to claim 1 is characterized by: The interception and solidification section of the sewage pipe includes the interception section and the solidification section. The sewage pipe above the shield tunnel is the solidification section, which is bounded by the inspection well. The interception section is located on the front and back sides of the solidification section. The end of the solidification section extends outward through an inspection well as the interception section.

10. The composite support construction method for shield tunneling under a sewage pipe at close range according to claim 9, characterized in that: A double airbag plugging system is provided in the interception section of the sewage pipe. Two airbags are provided in each interception section, and the two airbags are respectively provided at the two ends of the interception section.

Images