Earth pressure balance shield rapid tunneling construction method for high-water-rich round gravel stratum

Abstract

The invention discloses a high-water-rich round gravel stratum earth pressure balance shield rapid tunneling construction method, which belongs to the technical field of tunnel construction and comprises the steps of soil wall integrated cofferdam construction, weak muddy water mode conversion, shield tunneling and deep multi-component precise grouting construction. Wherein the bottom of the cofferdam is subjected to multi-component grouting reinforcement after water pumping of the cofferdam, and slurry of multi-component grouting comprises water, cement, clay, fly ash, bentonite, a water reducing agent, an accelerator and an early strength agent. According to the method, the riverway can be rapidly penetrated, meanwhile, the multi-component grout has the advantages of being good in stability, small in water separation property, controllable in setting time and the like, the phenomenon of water-rich round gravel stratum grout loss is effectively improved, meanwhile, the integrality and the self-bearing capacity of surrounding rock can be improved through deep multi-component precise grouting construction, the supporting cost is reduced, and the supporting effect is improved; various weak surfaces around the surrounding rock are filled and re-cemented by using the multi-component slurry, so that the physical and mechanical properties of the surrounding rock are improved, and the overall stability and impermeability of the surrounding rock are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a rapid excavation construction method of an earth pressure balance shield in a high-water-rich gravel stratum. Background Art

[0002] With the development of underground space, shield technology has been widely used in engineering fields such as subways, tunnels, municipal pipelines, etc. In various construction projects in my country, there are more and more types of shield machines, among which earth pressure balance shield machines have a relatively outstanding performance in subway construction.

[0003] In Zhejiang Province, tunnels often need to pass through high-water-rich gravel strata with high water content and large permeability coefficient. Especially when encountering a river channel, the pressurized water in the gravel layer is connected to the surface water, the shield tunneling causes great disturbance to the strata, and the screw conveyor is prone to gushing, which endangers the stability of the tunnel excavation surface. In addition, the soil cover at the bottom of the river channel is shallow. During the excavation process, the pressure of the soil bin can easily penetrate the soil surface, forming bubbles and slurry on the river surface, polluting the river channel; especially in strata similar to those in Hangzhou city, there are many surface rivers, complex water systems, and complex surrounding environments, which puts higher requirements on shield tunneling construction. How to quickly and safely complete the excavation construction and reduce the stratum deformation caused by the construction process is a major difficulty in this field.

[0004] The Chinese patent application publication number CN117988863A discloses a construction method for ultra-shallow shield crossing of a river in a water-rich sand layer area, which includes step 1, a construction method before ultra-shallow shield crossing of a river; step 2, a construction method for ultra-shallow shield crossing of a river. Before the shield passes through, Larsen steel sheet piles are used to block the river diversion section by section, and pull-out piles and anti-uplift cover plates are constructed in sections; the pull-out piles and anti-uplift cover plates form a whole, so that when the shield passes, the pressure of the shield on the riverbed will be borne by the anti-uplift cover plate first.

[0005] However, the anti-uplift cover plate of this scheme is cast with 50cm thick reinforced concrete. The overly thick reinforced concrete takes a long time to solidify and has high water separation, and laying the steel bars is time-consuming and laborious. At the same time, the cover plate of the above scheme only considers the anti-uplift problem, and does not consider improving the slurry loss phenomenon in the water-rich gravel stratum, and cannot play a good role in stratum reinforcement. At the same time, the tunnel construction direction of this scheme is perpendicular to the river direction, so two cofferdams are needed to ensure river diversion, but it is not suitable for the situation where the tunnel construction direction is the same as the river direction.

[0006] The Chinese patent with the authorization announcement number CN111852485B discloses a construction method for a shield tunnel in a shallow and weak stratum to pass under a sensitive building complex. The scheme effectively controls the surface settlement and deformation when the shield machine passes under, and ensures the safety of sensitive buildings through four steps: construction preparation, composite pre-grouting reinforcement treatment of the stratum, construction test in the non-underpassing section, and shield machine passing through the sensitive building complex. Step 2 of the scheme: composite pre-grouting reinforcement treatment of the stratum (equivalent to the anti-uplift cover plate set in CN117988863A); adopt two composite deep grouting methods, ground layered grouting and shield machine advance grouting, to arrange oblique grouting reinforcement holes around and below the sensitive buildings, and grouting reinforcement into the grouting reinforcement holes. The grouting slurry is a double liquid slurry composed of cement slurry and water glass slurry.

[0007] Conventional 1:1 water-cement ratio single-liquid slurry is easy to disperse and lose, while the cement slurry plus water glass double-liquid slurry in the above-mentioned document is uneven and has poor stability. The water-stopping property of the reinforced body cannot be guaranteed, and the strength is not easy to control. It is often the case that the strength of the reinforced body is too low to achieve the reinforcement effect, or the strength of the reinforced body is too high, making it difficult for the shield machine to excavate. Improper pressure control may cause the slurry to escape into the river, which can easily cause environmental pollution.

[0008] Therefore, there is an urgent need for a rapid excavation construction method for an earth pressure balance shield in a highly water-rich gravel formation, which can enable the earth pressure shield in the water-rich gravel formation to safely cross the river channel, while improving the slurry loss phenomenon in the water-rich gravel formation and maintaining the reinforcement of the formation. Summary of the invention

[0009] The object of the present invention is to provide a method for rapid excavation of an earth pressure balance shield in a highly water-rich gravel stratum, so as to solve the problems existing in the background technology.

[0010] The objective of the present invention is achieved through the following technical solutions: A method for rapid excavation of an earth pressure balance shield in a high water-rich gravel stratum comprises the following steps: S1: integrated cofferdam, including steps S11 to S12 S11: The side walls are made of steel sheet piles driven into the river channel. S12: The river bank backfill operation platform uses plain fill soil, and a layer of steel-plastic grating is laid for every 1m of backfill. The corners of the steel-plastic grating are welded and fixed to the steel sheet piles in S11 to form an integrated earth wall cofferdam. S2: After the cofferdam is pumped out, multi-component grouting is performed on the bottom of the cofferdam to reinforce it. The multi-component grouting slurry includes water, cement, clay, fly ash, bentonite, water reducer, accelerator, and early strength agent in the weight ratio of 5:10:5~6:0.1~0.2:0.015~0.03:0.15~0.25:0.015~0.03; S3: weak mud and water mode conversion, the shield machine is connected to the mobile weak mud and water device, mud is injected into the soil bin, and the soil bin environment is transformed into thick mud to stabilize the tunnel face; S4: Shield tunneling, including steps S41 to S43, S41: Test excavation stage, S42: The stage of excavation through the river channel, S43: Post-crossing observation phase; Wherein both step S41 and step S42 are provided with step S44: deep multi-component precision grouting construction.

[0011] Furthermore, in step S11, double-layer SP-IV type Larsen steel sheet piles are used as the steel sheet piles, the spacing between the two layers of steel sheet piles is 0.5m, and the middle is densely filled with sandbags. The length of the steel sheet piles is 12m, and they are inserted 6m below the riverbed.

[0012] Furthermore, in step S2, skip hole construction is adopted before grouting, and the grouting reinforcement range is 1m above, below, left and right of the shield excavation range. The drilling holes are arranged in a plum blossom shape with a hole spacing of 1.5m×1.5m and a hole diameter of 108mm. Sleeve valve pipe devices are buried in the drilling holes, and small screw grouting equipment is used to pour active bentonite and early-setting and early-strength cement as casing materials between the outer side of the sleeve valve pipe device and the wall of the drilling hole.

[0013] Furthermore, 48 hours after the grouting of the shell material is completed, a double stopper tube is placed along the inner side of the sleeve valve tube. The double stopper tube is fixed to the inner wall of the sleeve valve tube device by pressurizing. First, grouting operation is carried out along the lower end of the sleeve valve tube. The grouting pressure of the first grouting hole in the skip hole construction is 0.3~0.5MPa, and the grouting pressure of the subsequent supplementary grouting holes is 0.5~0.8MPa. The interval time between grouting of adjacent holes is greater than 24 hours.

[0014] Furthermore, both step S41 and step S42 inject the mud effect through the radial holes of the shield shell of the shield machine, and the injection points of the mud effect are at 1 o'clock and 11 o'clock.

[0015] Furthermore, in step S41 and step S42, synchronous grouting is performed when the segment is separated from the shield tail, and every ten rings of the segment are sealed once with a double liquid slurry of cement and water glass.

[0016] Furthermore, in step S44, a φ48 steel flower pipe with a wall thickness of 3 mm is used, slurry outlet holes are prefabricated on the rod, the pipe body is wrapped with three turns of plastic film, a reverse check device is set at the grouting end, and the advance grouting hole of the shield machine is used to punch into the steel flower pipe and inject slurry. The grouting slurry includes cement slurry, fly ash, slag powder, and accelerator, wherein the water-cement ratio in the cement slurry is 1.5:1.

[0017] Furthermore, in step S4, a shutdown and maintenance point is set during the shield machine excavation to perform maintenance on the shield machine equipment, and the tool wear is analyzed according to the shield machine parameters. If there is an abnormality in the tool, the tool is replaced by bringing it into the chamber with pressure.

[0018] The beneficial effects of the present invention are: 1) Rapid and efficient excavation of tunnels under rivers effectively avoids problems such as mud and water gushing, segment leakage, and river pollution during excavation, so that the earth pressure shield in water-rich gravel strata can safely cross the river.

[0019] 2) The use of multi-component slurry has the advantages of good stability, low water separation, and controllable setting time. It can effectively improve the slurry loss phenomenon in water-rich gravel formations and play a good role in stratum reinforcement.

[0020] 3) The backfill soil and cofferdam can form a whole, avoiding the situation where the steel sheet piles are squeezed and deformed when the steel sheet piles are driven into the soft soil and the backfill working platform is directly backfilled. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flow chart of the construction method of the present invention; Figure 2 It is a schematic diagram of the multi-component grouting area in the present invention; Figure 3 This is a schematic diagram of the deep multi-component precision grouting construction arrangement of the present invention; In the figure, 1-steel flower pipe, 2-deep multi-component grouting reinforcement, 3-shield machine, 4-multi-component grouting area, 5-multi-component grouting hole position, 6-cofferdam, 7-tunnel construction scope. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1-Figure 3 , the present invention provides a technical solution: like Figure 1-Figure 3As shown, a method for rapid excavation of an earth pressure balance shield in a high water-rich gravel formation is first to construct a steel sheet pile cofferdam for the river channel and pump water, and to form an integrated earth wall cofferdam by welding steel-plastic grids during the backfilling process, and then to perform multi-component grouting reinforcement, and then the earth pressure balance shield machine is converted to a weak mud-water mode, and excavates and crosses, and finally performs deep multi-component precision grouting construction. The present invention reasonably designs the construction sequence, and while quickly and efficiently excavating the construction tunnel under the river channel, effectively avoids the problems of sudden mud and water gushing, pipe segment leakage, and river channel pollution during the excavation process, so that the earth pressure shield in the water-rich gravel formation can safely cross the river channel.

[0024] Step S1: integrated cofferdam, including steps S11 to S12, wherein Figure 2 As shown, the cofferdam 6 S11: The side walls are made of steel sheet piles driven into the river channel. S12: The river bank backfill operation platform uses plain fill soil, and a layer of steel-plastic grating is laid for every 1m of backfill. The corners of the steel-plastic grating are welded and fixed to the steel sheet piles in S11 to form an integrated earth wall cofferdam. The side walls are driven into the river channel with steel sheet piles. In step S11, the steel sheet piles are double-layer SP-IV type Larsen steel sheet piles. The size of a single steel sheet pile is 400mm*150mm*13mm. The distance between the two layers of steel sheet piles is 0.5m. The middle is densely filled with sandbags. The total length of the steel sheet piles is 12m, and they are inserted 6m below the riverbed.

[0025] Specifically, Figure 2 As shown, the direction of the tunnel construction range 7 is the same as the direction of the river channel, the width of the river channel is greater than the width of the tunnel construction range 7, and the cofferdam 6 only surrounds part of the river channel to ensure that the river channel can be smoothly diverted.

[0026] Among them, during the construction process of step S11, the following steps are also included: S111: Lay out the accurate center line of steel sheet piles according to the geological conditions under the river channel; S112: Before piling, check each steel sheet pile and apply grease to the locking mouth of the steel sheet pile; S113: 10-20 steel sheet piles are inserted into the guide frame in a row to form a screen shape. The two sides of a group of steel sheet piles are first driven to the design elevation and welded to the external purlin. The middle of a group of steel sheet piles are driven in sequence at 1 / 3 or 1 / 2 of the design height. When the two ends of a group of steel sheet piles are reversely tilted after being driven, the steel sheet piles in the middle should be driven in a forward sequence; otherwise, they should be driven in a reverse sequence; when the two ends of a group of steel sheet piles remain vertical, the steel sheet piles in the middle are driven in a reciprocating sequence; during the driving process, the inclination of the steel sheet piles shall not exceed 1% of the design height of the steel sheet piles. When the deflection is too large to be adjusted by the pulling method, pull it out and drive it again; S114: After the steel sheet piles are driven in, the water-tightness check is carried out. When the pile-following phenomenon occurs in the soft foundation, several adjacent steel sheet piles are welded together, and lubricants such as butter are applied to the connection locks of the steel sheet piles to reduce resistance; S115: Pumping out water after construction is completed.

[0027] S12: The river bank backfill operation platform uses plain fill soil, and a layer of steel-plastic grating is laid for every 1m of backfill. The corners of the steel-plastic grating are welded and fixed to the steel sheet piles in S11 to form an integrated earth wall cofferdam. Through step S12, the backfill soil and the cofferdam can form a whole, avoiding the situation where the steel sheet piles are squeezed and deformed when the steel sheet piles are directly backfilled in the soft soil.

[0028] Step S2: after the cofferdam is pumped out, multi-component grouting reinforcement is performed on the bottom of the cofferdam, wherein the multi-component grouting slurry comprises water, cement, clay, fly ash, bentonite, water reducing agent, accelerator, and early strength agent, in a weight ratio of 5:10:5~6:0.1~0.2:0.015~0.03:0.15~0.25:0.015~0.03; The slurry used in multi-component grouting is a multi-component slurry that reduces the amount of cement by adding admixtures such as clay, fly ash, bentonite, and water reducers, accelerators, and early strength agents to cement slurry. The water-cement ratio is generally determined to be 1:0.5, and the remaining clay, bentonite, water reducers, accelerators, and early strength agents are determined through field tests, that is, no less than three groups of proportion tests are carried out according to geological conditions, and the slurry setting time, setting strength, and flow state are observed, and the best proportion is obtained through comprehensive analysis. The test data of multi-component slurry proportions are as follows: Multi-component slurry ratio test (unit: kg) Through field tests, the initial setting time of the mix ratio of No. 2 is 10 minutes, the final setting strength is about 1MPa, and the slurry viscosity is moderate. The slurry mix ratio of No. 2 is preferred for construction.

[0029] By adopting multi-component slurry, which has the advantages of good stability, low water separation, and controllable setting time, the grouting consolidation body has good density, high strength, and good durability. Its characteristics perfectly match the engineering characteristics of the gravel formation, effectively improving the slurry loss phenomenon in the water-rich gravel formation, and playing a better role in stratum reinforcement.

[0030] Step S13: Before grouting, skip hole construction is adopted. Figure 2As shown in the figure, the range of the multi-group grouting area 4 is 1m above, below, left and right of the shield excavation range, and the multi-component grouting hole positions 5 are arranged in a plum blossom shape, with a hole spacing of 1.5m×1.5m and a hole diameter of 108mm. The drill hole is buried in a sleeve valve pipe device, and a small screw grouting equipment is used to inject active bentonite and early-setting and early-strength cement as casing materials between the outer side of the sleeve valve pipe device and the drill hole wall.

[0031] Among them, the shell material is poured in the form of toothpaste-like thick slurry, the water-cement ratio is controlled at about 0.3, and the grouting is performed layer by layer from bottom to top or after closing, the grouting nozzle is installed for pressure grouting. The shell material can play a certain strength of sealing and protection around the sleeve valve pipe.

[0032] Furthermore, 48 hours after the grouting of the casing material is completed, a double stopper tube is placed along the inner side of the sleeve valve tube. The double stopper tube is fixed to the inner wall of the sleeve valve tube device by pressurizing, and grouting operation is first performed along the lower end of the sleeve valve tube.

[0033] The sleeve valve tube device and the double stopper tube are existing technologies. When slurry enters between the sleeve valve tube and the double stopper tube, the rubber cap is pushed up under the action of pressure. As the slurry accumulates and the pressure reaches a certain level, the rubber cap on the outside of the sleeve valve tube is opened and the shell material is crushed, so that the slurry is squeezed into the formation. The shell materials on the upper and lower parts of the outside of the sleeve valve tube have a certain strength, which can prevent the slurry from flowing up and down, so that the slurry can flow horizontally within a certain range. When the pressure outside the sleeve valve tube is greater than that inside the tube, the rubber sleeve outside the small hole automatically closes.

[0034] Furthermore, the grouting pressure of the first grouting holes in the skip hole construction is 0.3-0.5 MPa, the grouting pressure of the subsequent supplementary grouting holes is 0.5-0.8 MPa, and the interval time between grouting of adjacent holes is greater than 24 hours.

[0035] The purpose of sequential grouting through the grouting holes is to ensure the grouting effect according to the principle of gradual density of pressure grouting. At the same time, after the construction of each grouting hole is completed, the actual cement consumption is compared with the theoretical cement consumption. When the actual cement consumption is less than the theoretical amount, the steel sheet pile is drilled and supplemented with grouting. The grouting process adopts a control method based on grouting volume as the main and grouting pressure as the auxiliary.

[0036] The multi-component grouting construction adopted in the present invention has little disturbance to the stratum. The deformation of the ground after grouting is within ±2mm. After coring detection, the reinforced body is uniform and dense, the core sample is complete and continuous, and the unconfined compressive strength test is carried out. The soil strength is controlled between 1 and 5MPa, which can not only meet the water-stopping requirements, but also ensure that the shield machine can pass easily. Due to the different diffusion degrees of the grouting holes in the stratum, the stratum strength changes significantly with the deepening of the drilling depth. The on-site drilling revealed that the reinforcement effect is obvious and there is basically no water seepage and hole collapse. It can be seen that the multi-component grouting reinforcement technology has an obvious reinforcement effect on the round gravel stratum, and the slurry diffusion range can be effectively controlled.

[0037] Step S3: weak mud water mode conversion, the earth pressure balance shield machine is connected to the mobile weak mud water device, mud is injected into the soil bin, and the soil bin environment is transformed into thick mud to stabilize the tunnel face.

[0038] Through the above technical solution, the earth pressure balance shield machine is equipped with a mobile weak mud water device, which is the prior art. Refer to the Chinese patent mud water TBM and mud water balance shield machine and control method thereof with authorization announcement number CN109252871A, in which the mobile weak mud water device includes a mud water storage tank, a pumping system, a filtering system and a control system. The mud water storage tank is used to store the prepared mud water, the pumping system is responsible for transporting the mud water to the excavation face of the shield machine, and the filtering system is used to filter and purify the discharged mud water to realize the recycling of mud water. The control system can realize the automatic control of the entire device to ensure the stability and reliability of its operation.

[0039] Step S4: Shield tunneling, including steps S41 to S43. S41: Test excavation phase, S42: The stage of excavation through the river channel, S43: Post-crossing observation phase; In both step S41 and step S42, the mud effect is injected through the radial holes of the shield shell of the shield machine, and the injection points of the mud effect are at 1 o'clock and 11 o'clock.

[0040] Furthermore, in step S41 and step S42, synchronous grouting is performed when the segment is separated from the shield tail, and every ten rings of the segment are sealed once with a double liquid slurry of cement and water glass.

[0041] Furthermore, in step S4, a shutdown and maintenance point is set during the shield machine excavation to perform maintenance on the shield machine equipment, and the tool wear is analyzed according to the shield machine parameters. If there is an abnormality in the tool, the tool is replaced by bringing it into the chamber with pressure.

[0042] Wherein step S41 and step S42 are both provided with step S44: deep multi-component precision grouting construction. Figure 3As shown, in step S44, a φ48 steel tube 1 is used, the wall thickness of the steel tube 1 is 3 mm, a grouting hole is prefabricated on the rod, the tube body of the steel tube 1 is wrapped with a plastic film three times, a reverse check device is set at the grouting end, and the advance grouting hole of the shield machine 3 is used to drive into the steel tube 1 and inject slurry. The grouting slurry includes cement slurry, fly ash, slag powder, and quick-setting agent, wherein the water-cement ratio in the cement slurry is 1.5:1. After grouting, a deep multi-component grouting reinforcement body 2 is formed.

[0043] Step S44 uses advanced multi-component precision grouting to improve the integrity and self-bearing capacity of the surrounding rock, reduce support costs, and improve support effects. Multi-component slurry is used to enrich and re-cement various weak surfaces around the surrounding rock, improve the physical and mechanical properties of the surrounding rock, and thus improve the overall stability and impermeability of the surrounding rock.

[0044] In the construction of advanced multi-component precision grouting, a check device is installed in the grouting hole, including a membrane bag, a plug, an injection plug, and a sleeve valve tube. It mainly refers to putting the membrane bag on the outside of the sleeve valve tube. After the drilling rig drills a hole in the soft stratum, the sleeve valve tube is placed in the grouting hole, and the slurry is injected into the membrane bag through the sleeve valve tube by pressure grouting. After the slurry is injected, the membrane bag slowly opens in the hole to form an effective bearing layer with the surrounding soil, jointly bearing the upper load and achieving the reinforcement effect. At the same time, the plug and injection plug prevent the slurry from flowing back and ensure the grouting effect. Furthermore, the grouting slurry for deep multi-component precision grouting construction also uses multi-component slurry with a water-cement ratio of 1.5:1. Because the slurry needs to be filled densely to form a grouting ring outside the pipe segment, and it is required to be "deep" and "precise", fly ash and slag powder need to be added to the slurry to improve fluidity. At the same time, adding an accelerator can prevent the slurry from being lost in the gravel layer. The amount of multi-component materials is determined through field tests, and no less than three groups of proportion tests are carried out according to the geological conditions to observe the slurry setting time, setting strength and flow state of the slurry, and the best ratio is obtained through comprehensive analysis. The slurry is prepared by on-site mixing, and the specific proportion test is as follows: Deep multi-component precision grouting slurry ratio test (unit: kg) Serial number cement water Fly ash Slag powder Accelerator 1 5 7.5 0.5 0.5 0.15 2 5 7.5 0.5 0.5 0.25 3 5 7.5 0.5 0.8 0.25 Through field tests, the initial setting time of the mix ratio of No. 1 is 15min, the final setting strength is about 5MPa, and the slurry fluidity meets the requirements. The slurry ratio of No. 1 is preferred for construction. When grouting, the grouting pump is first started to pump water to open the grouting channel, and then the slurry is injected. The grouting process is mainly controlled by the grouting volume, and the grouting pressure is used as a reference. The grouting volume is about 4.5m³ / hole, and the grouting pressure is generally 0.6~1.2MPa. At the same time, after the grouting is completed, the grouting hole is sealed with double liquid slurry to prevent water seepage.

[0045] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not depart from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for rapid excavation of an earth pressure balance shield in a high water-rich gravel stratum, characterized by: The following steps are involved: S1: integrated cofferdam, including steps S11 to S12, S11: The side walls are made of steel sheet piles driven into the river channel; S12: The river bank backfill operation platform adopts plain fill soil, and a layer of steel-plastic grid is laid for every 1m of backfill. The corners of the steel-plastic grid are welded and fixed to the steel sheet piles in S11 to form an integrated earth wall cofferdam; S2: After the cofferdam is pumped out, multi-component grouting is performed on the bottom of the cofferdam to reinforce it. The multi-component grouting slurry includes water, cement, clay, fly ash, bentonite, water reducer, accelerator, and early strength agent in the following weight ratios: 5:10:5~6:0.1~0.2:0.015~0.03:0.15~0.25:0.015~0.

03. S3: Weak mud and water mode conversion: the shield machine is connected to a mobile weak mud and water device to inject mud into the soil bin, transforming the soil bin environment into thick mud to stabilize the tunnel face. S4: Shield tunneling, including steps S41 to S43, S41: Test excavation stage, S42: The stage of excavation through the river channel, S43: Post-crossing observation phase; Wherein both step S41 and step S42 are provided with step S44: deep multi-component precision grouting construction.

2. The method for rapid excavation of an earth pressure balance shield in a high water-rich gravel stratum according to claim 1 is characterized in that: In step S11, double-layer SP-IV type Larsen steel sheet piles are used as the steel sheet piles. The spacing between the two layers of steel sheet piles is 0.5m, and the middle is densely filled with sandbags. The length of the steel sheet piles is 12m, and they are inserted 6m below the riverbed.

3. The method for rapid excavation of an earth pressure balance shield in a high water-rich gravel stratum according to claim 1 is characterized by: In step S2, skip hole construction is adopted before grouting. The grouting reinforcement range is 1m above, below, left and right of the shield excavation range. The grouting holes of multi-component grouting are arranged in a plum blossom shape, with a hole spacing of 1.5m×1.5m and a hole diameter of 108mm. The sleeve valve pipe device is buried in the drilling hole, and a small screw grouting equipment is used to pour active bentonite and early-setting and early-strength cement as casing materials between the outer side of the sleeve valve pipe device and the drilling hole wall.

4. The method for rapid excavation of an earth pressure balance shield in a high water-rich gravel stratum according to claim 3 is characterized by: 48 hours after the grouting of the shell material is completed, a double plug tube is placed along the inside of the sleeve valve tube. The double plug tube is fixed to the inner wall of the sleeve valve tube device by pressurizing. First, grouting is carried out along the lower end of the sleeve valve tube. The grouting pressure of the first grouting hole in the skip hole construction is 0.3~0.5MPa, and the grouting pressure of the subsequent supplementary grouting holes is 0.5~0.8MPa. The interval time between grouting of adjacent holes is greater than 24 hours.

5. The method for rapid excavation of an earth pressure balance shield in a high water-rich gravel stratum according to claim 1 is characterized by: In both step S41 and step S42, the mud effect is injected through the radial holes of the shield shell of the shield machine, and the injection points of the mud effect are at 1 o'clock and 11 o'clock.

6. The method for rapid excavation of an earth pressure balance shield in a high water-rich gravel stratum according to claim 1 is characterized by: In step S41 and step S42, synchronous grouting is performed when the segments are separated from the shield tail, and every ten rings of segments are sealed once with a double liquid slurry of cement and water glass.

7. The method for rapid excavation of an earth pressure balance shield in a high water-rich gravel stratum according to claim 1 is characterized by: In step S44, a φ48 steel tube with a wall thickness of 3 mm is used. A slurry outlet hole is prefabricated on the rod. The tube body is wrapped with three turns of plastic film. A reverse check device is set at the grouting end. The advance grouting hole of the shield machine is used to punch into the steel tube and inject slurry. The grouting slurry includes cement slurry, fly ash, slag powder, and accelerator, wherein the water-cement ratio in the cement slurry is 1.5:

1.

8. The method for rapid excavation of an earth pressure balance shield in a high water-rich gravel stratum according to claim 1 is characterized by: In step S4, a stop and maintenance point is set during the shield machine excavation to perform maintenance on the shield machine equipment, and the tool wear is analyzed according to the shield machine parameters. If there is an abnormality in the tool, the tool is replaced by bringing it into the chamber with pressure.

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