A slurry injection system and method for a shield machine

Abstract

The present application relates to a kind of shield machine shield shell thick slurry injection system and method, to solve the technical problem of control complex, poor self-adaptability, scheme in the middle shield grouting pressure between shield and soil layer and the front shield grouting pressure between front shield and soil layer and with soil chamber pressure form interlock control;If middle shield grouting pressure and front shield grouting pressure all do not reach grouting pressure target, through the tail shield grouting hole set on tail shield shell body and the front shield grouting hole set on front shield shell body grouting;If front shield grouting pressure reaches grouting pressure target, middle shield grouting pressure does not reach grouting pressure target, only through tail shield grouting hole grouting;If middle shield grouting pressure reaches grouting pressure target, stop grouting.The scheme of the present application guarantees that slurry does not enter soil chamber, and can also make middle shield form dense annular cavity, to achieve the purpose of intelligent injection of anti-settling.

Description

Technical Field

[0001] This invention relates to a system and method for injecting thick slurry into the shield shell of a tunnel boring machine, belonging to the field of tunnel construction technology. Background Technology

[0002] like Figure 1 As shown, during the tunnel boring machine's (TBM) excavation process, because the excavation diameter of the cutterhead 11 is larger than the diameter of the shield body 12 and the lining segments, there is a risk of settlement during construction. Timely filling of the excavation gaps is crucial to prevent surface subsidence and achieve the predetermined surface settlement target. Currently, synchronous grouting and secondary grouting are commonly used to fill the gaps between the back of the lining segments and the tunnel wall 13, preventing loosening and water leakage of the surrounding rock and thus preventing surface settlement. However, while synchronous grouting controls settlement between the shield tail and the lining segments, a ring-shaped gap still exists in the front and middle shield areas of the TBM. When the TBM passes through this gap, there is still a risk of settlement and shield jamming. Furthermore, due to the solidification characteristics of the synchronous grout, there is a risk that the grout may flow around the shield body. Prolonged shutdown can cause the grout to encapsulate the shield body, making it difficult to control the shield's attitude deviation during subsequent excavation.

[0003] The Chinese patent announcement (CN212428858U) discloses a grouting control system for preventing ground settlement during tunnel boring machine (TBM) excavation. This system involves arranging multiple grouting holes on the shield body and controlling grouting in the corresponding holes based on the pressure within the corresponding grouting pipeline. This system requires multiple grouting pipelines, and to achieve the best results, as many grouting holes as possible and evenly distributed across the shield body are needed. Each pipeline must be equipped with a pneumatic ball valve and a pressure sensor. Since the pressure sensor can only detect the pressure at the injection point and cannot detect the pressure within the annular cavity, to ensure reliable grouting and prevent ground settlement, manual control of grouting in each pipeline based on experience and pressure is necessary. This control method is complex and costly; furthermore, it lacks adaptability to changes in the TBM's operating conditions.

[0004] Chinese patent publication CN108868799A discloses a synchronous grouting structure and construction auxiliary system for earth pressure balance shield tunneling. Compared to the previous solution, it adds the function of adjusting the grouting volume according to the tunneling speed. However, the core of the solution still relies on the empirical value of 105% of the filling volume to manually guide the actual grouting volume of the injection system. When the shield is long and the tunneling conditions are complex and variable, single-point injection pressure detection and empirical grouting volume cannot guarantee the formation of a complete annular cavity for the grout, and it lacks good adaptability. Summary of the Invention

[0005] The purpose of this invention is to provide a method for injecting thick grout into the shield shell of a tunnel boring machine, which solves the problems of complex control and poor adaptability of existing grouting control methods; it also provides a system for injecting thick grout into the shield shell of a tunnel boring machine, which solves the problems of high cost and complex control of existing grouting systems.

[0006] To achieve the above objectives, the present invention includes: The present invention discloses a technical solution for injecting thick grout into the shield shell of a tunnel boring machine. The method involves collecting the grouting pressure between the middle and rear sections of the shield and the soil layer, as well as the grouting pressure between the front section of the shield and the soil layer. If neither the middle / rear nor the front grouting pressure reaches the target grouting pressure, grouting is performed through the middle / rear grouting holes on the middle / rear shell and the front grouting holes on the front shell. If the front grouting pressure reaches the target grouting pressure, but the middle / rear grouting pressure does not, grouting is performed only through the middle / rear grouting holes. Grouting is stopped when the middle / rear grouting pressure reaches the target grouting pressure.

[0007] This invention monitors the grouting pressure at the front and controls the grouting of the front and middle / rear sections by interlocking the grouting pressure at the front with the soil chamber pressure. When neither the front nor the middle / rear sections reach the target grouting pressure, grouting occurs simultaneously at both. When the front reaches the grouting pressure but the middle / rear sections do not, grouting at the front shield stops to prevent thick grout from seeping into the soil chamber, while grouting only occurs at the middle / rear section. The grouting pressure at the front reaches a higher value than that at the middle / rear section, causing the grout to remain in the middle / rear section, forming a dense annular cavity. This achieves intelligent injection under simple control to prevent settlement. Grouting stops when the middle / rear section reaches the grouting pressure, at which point a stable annular cavity is considered to have formed from the pressure detection point to the middle / rear injection hole area.

[0008] Furthermore, the grouting pressure target is set based on the soil chamber pressure at a vertical height position that is the same as or similar to the corresponding grouting pressure collection point.

[0009] The soil pressure at the same height within the soil chamber is used as the target value for grouting pressure. This target value can be set within a certain threshold range as needed to prevent excessively high local grouting pressure from causing thick grout to enter the soil chamber. The soil chamber pressure can be obtained from pressure sensors on the soil chamber partition.

[0010] Those skilled in the art should understand that the same height does not mean that the heights are absolutely the same. This is neither necessary nor easy to implement in engineering practice. Therefore, the soil pressure at the height position within a certain allowable error range should be regarded as the target value of the grouting pressure and fall within the protection scope of this invention.

[0011] Furthermore, the grouting pressure of the front shield is collected by a front shield pressure sensor arranged in a ring direction on the outer periphery of the front shield body; the grouting pressure of the middle and rear middle shield is collected by a middle shield pressure sensor arranged in a ring direction on the outer periphery of the middle shield body; the front shield pressure sensor and the middle shield pressure sensor on the same straight line in the shield body axis constitute a set of pressure sensors. The front grouting holes are arranged around the outer circumference of the front shield, and the middle and rear grouting holes are arranged around the outer circumference of the tail shield; the front grouting holes and the middle and rear grouting holes on the same straight line in the axial direction of the shield body constitute a set of grouting holes. Each set of grouting holes and each set of pressure sensors are arranged at intervals around the shield body.

[0012] Furthermore, if the detection value of a certain front shield pressure sensor reaches the grouting pressure target, then the lower front grouting hole adjacent to that pressure sensor is closed; if the detection value of a certain middle shield pressure sensor reaches the grouting pressure target, then the lower front grouting hole and the middle and rear grouting hole adjacent to that pressure sensor are closed.

[0013] The method of this invention groups the monitored grouting pressure and grouting location along the circumference of the shield body, with the groups for monitoring grouting pressure and grouting location distributed at intervals along the circumference. When the monitoring point at the corresponding location reaches the target pressure, grouting at the adjacent lower grouting location is stopped, making the control more precise, the grouting injection more uniform, and the thick grout in the annular cavity more compact.

[0014] Furthermore, in order to control the grouting of the front shield based on the grouting pressure of the front shield and prevent grout from entering the soil chamber, the front shield pressure sensor is set on one side of the cutterhead of the front grouting hole and at a certain axial distance from the front grouting hole.

[0015] Furthermore, in order to achieve overall matching between grouting speed and tunneling speed and realize the purpose of intelligent grout injection, when the tunneling speed of the tunnel boring machine changes, the output speed of the thick grout in the grouting pipeline is adjusted according to the pre-calibrated correspondence.

[0016] The present invention discloses a technical solution for a thick grout injection system for a tunnel boring machine shield shell, comprising a grout preparation unit for preparing thick grout for filling the gap between the shield body and the tunnel wall, a grouting pipeline system connected to the grout preparation unit for conveying the thick grout, and a detection and control unit; the grouting pipeline system includes a front grouting hole for outputting grout between the front of the shield body and the tunnel wall, a middle and rear grouting hole for outputting grout between the middle and rear of the shield body and the tunnel wall, and valves for controlling the opening and closing of the front grouting hole and the middle and rear grouting hole; the detection and control unit includes a front pressure sensor for detecting the soil and water pressure at the front of the shield body and a middle and rear pressure sensor for detecting the soil and water pressure at the middle and rear of the shield body.

[0017] The injection system of this invention eliminates the need to monitor the grouting pressure within the grouting pipeline, thus reducing costs while ensuring dense grouting. The injection position of each grouting hole in this invention is determined based on parameters such as actual working conditions and grout flow direction analysis.

[0018] Furthermore, the pressure sensors of the front shield are arranged in a circumferential direction on the outer periphery of the front shield; the pressure sensors of the middle and rear shield are arranged in a circumferential direction on the outer periphery of the middle shield; the grouting holes of the front shield are arranged in a circumferential direction on the outer periphery of the front shield, and the grouting holes of the middle and rear tail shield are arranged in a circumferential direction on the outer periphery of the tail shield; the pressure sensors of the front shield and the pressure sensors of the middle and rear shield are arranged in groups; the grouting holes of the front shield and the grouting holes of the middle and rear tail shield are arranged in groups, and each pressure sensor and each group of grouting holes is located on a straight line along the same shield axis, while each group of grouting holes and each group of pressure sensors are arranged at intervals in the circumferential direction of the shield.

[0019] The system of the present invention groups the pressure sensor and the grouting hole, which is beneficial to further optimize the control process and improve the control precision.

[0020] Furthermore, the front pressure sensor and the middle and rear pressure sensor in the same group are close to the soil pressure sensor used to measure the soil pressure in the radial direction of the shield body.

[0021] The soil chamber pressure sensor and the grouting pressure sensor that are close in the radial direction can respectively collect the soil chamber pressure and the grouting pressure at similar positions at the same vertical height. This facilitates the interlocking of the soil chamber pressure and the target grouting pressure, and helps to prevent grout from entering the soil chamber due to the grouting pressure exceeding the soil chamber pressure at adjacent positions.

[0022] Furthermore, the grouting pipeline system includes a main grouting pipeline directly connected to the grout preparation unit. The main grouting pipeline is connected to tail shield grouting pipelines corresponding to the same group of tail shield grouting holes. Each tail shield grouting pipeline is connected to the same group of tail shield grouting holes via tail shield grouting piping. The main grouting pipeline is also connected to front shield grouting pipelines corresponding to the same group of front shield grouting holes. Each front shield grouting pipeline is connected to the same group of front shield grouting holes via front shield grouting piping. Both the tail shield grouting piping and the front shield grouting piping are equipped with check valves and on / off valves.

[0023] The system of the present invention can realize unified control of the opening and closing of grouting holes of corresponding shield bodies in the same group, or can control each grouting hole independently. The former simplifies control, while the latter enables more precise control.

[0024] Furthermore, in order to achieve adjustable grouting speed, a grouting pump for adjusting the output speed of thick grout is also installed in the main grouting pipeline before connecting the tail shield grouting pipeline and the front shield grouting pipeline.

[0025] Furthermore, in order to enable flushing of the grouting pipeline along the slurry flow direction, the two ends of the main grouting pipeline are respectively provided with interfaces for pipeline flushing. A flushing water inlet valve and a one-way valve facing the other end are provided between the connection point connected to the slurry preparation unit and the corresponding end interface. A flushing drain valve is provided between the connection point connected to the front shield grouting pipeline and the corresponding end interface.

[0026] Furthermore, the front pressure sensor is located on one side of the front grouting hole cutterhead and at a certain axial distance from the front grouting hole of the shield body. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the external shield of a tunnel boring machine; Figure 2 This is a schematic diagram of a thick slurry injection system for the shield shell of a tunnel boring machine according to the present invention; Figure 3(a) is a schematic diagram of the slurry injection holes and grouting pressure sensors of the present invention distributed at intervals around the shield body (the top and bottom are the injection holes). Figure 3(b) is a schematic diagram of the grout injection holes and grouting pressure sensors of the present invention distributed at intervals around the shield body (the top and bottom are pressure sensors).

[0028] The diagram includes: 11. Cutterhead; 12. Shield body; 13. Tunnel wall; 21. Dry powder slurry tank; 22. Weighing sensor; 23. Discharge valve; 24. Horizontal screw conveyor; 25. Inclined screw conveyor; 26. Slurry tank; 27. B liquid tank; 28. B liquid transfer pump; 29. ​​Discharge control valve; 30. Main grouting pipeline; 31. Tail shield grouting pipeline; 311. Tail shield grouting piping; 312. Tail shield grouting port; 32. 321. Front shield grouting pipeline; 322. Front shield grouting port; 33. Grouting control pneumatic ball valve; 34. Check valve; 35. Manual ball valve; 36. Cleaning water discharge valve; 37. Flushing check valve; 38. Cleaning water control valve; 39. Hydraulic grouting pump; 40. PLC controller; 41. Shield grouting pressure sensor; 42. Hydraulic control section; 421. Hydraulic oil source; 43. Excavation chamber earth pressure sensor. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0030] System Implementation Example: One objective of this invention is to provide an intelligent injection system for thick slurry in the shield shell of a tunnel boring machine.

[0031] The intelligent slurry injection system of the present invention comprises: 1) a slurry preparation system for preparing and transporting slurry; 2) a grouting pipeline system for distributing slurry to different locations on the shield body; 3) a shell pressure sensor for monitoring the pressure in a certain area of ​​the shield shell annular cavity; and 4) a baffle pressure sensor for monitoring the water and soil pressure in the soil chamber. Specifically, the grouting pipeline system includes: a grouting control pneumatic ball valve for closing (opening) the slurry injection in different areas of the pipeline; a one-way valve to prevent backflow of slurry or other liquids; a manual ball valve for closing (opening) a single injection hole; and a wastewater discharge pipeline and a pneumatic ball valve for flushing the grouting pipeline and discharging the wastewater to a designated location.

[0032] In the intelligent injection system of this invention, after the grout preparation is completed, the injection of thick grout into the front and tail shield areas is achieved by opening a control pneumatic ball valve. Pressure sensors are installed on the shield shells of the middle and front shields. The pressure sensor on the front shield is located at a certain axial distance from the injection hole in the tunneling direction. The monitoring values ​​of the pressure sensors on the front and middle shields are interlocked with the monitoring values ​​of the soil chamber pressure sensor, thereby intelligently adjusting the injection volume of thick grout during tunneling. The system control can set the injection time to reach the set pressure according to construction requirements. When the tunneling speed of the tunnel boring machine changes, the proportional speed control valve of the grouting pump in the grouting system starts to operate under the control of the PLC, thereby automatically adjusting the injection speed of the thick grout to achieve the requirements of intelligent injection.

[0033] The slurry preparation system of the present invention is used for the automatic preparation and injection of slurry, and can realize functions such as continuous slurry preparation, automatic slurry injection, automatic cleaning and data recording.

[0034] The slurry preparation section of the intelligent slurry injection system of the present invention comprises: a dry powder tank for storing dry powder slurry, and a discharge valve for controlling the conveying of dry powder (aggregate); a horizontal screw conveyor and an inclined screw conveyor for conveying aggregate to the slurry tank; a dry powder weighing sensor for measuring and recording the amount of aggregate used to match the required mixing ratio during the slurry preparation process; a slurry tank for stirring and storing thick slurry; a coagulant (B liquid) tank and a B liquid pump for storing coagulant and pumping it to the slurry tank for mixing with aggregate; a slurry tank discharge control valve and a slurry pump for opening the control valve and the slurry pump to convey slurry; a slurry pump inlet check valve and a cleaning water control valve for flushing the pump body and pipeline after slurrying; and a cleaning water discharge valve for timely discharge of wastewater after cleaning the slurry pump and pipeline to a designated wastewater tank or other area.

[0035] In the slurry preparation section of this invention, as described above, when the equipment begins tunneling, the thick slurry preparation system equipped on the tunnel boring machine starts operating. During the slurry preparation process, automatic batching, slurry preparation, and conveying can be performed through the control system. A dry powder tank is matched with the tunnel material train for storing the dry powder slurry. The aggregate in the dry powder tank is conveyed to the slurry preparation tank through a discharge valve and a conveying screw conveyor. Simultaneously, coagulant B liquid from the coagulant B liquid tank is conveyed to the slurry preparation tank. After the two slurries are mixed in the slurry preparation tank, automatic grouting is performed through a grouting pump. The configured cleaning pipeline can be automatically cleaned after the grouting pump stops working. Simultaneously, by recording data from the dry powder weighing sensor and the B liquid conveying pump 28, and through program calculation, the required ratio of slurries with different specific gravities is achieved, realizing functions such as continuous slurry preparation, automatic grouting, automatic cleaning, and data recording.

[0036] Specifically, the present invention provides an intelligent injection system for thick slurry in the shield shell of a tunnel boring machine, comprising a slurry preparation section, a grouting pipeline system, and a detection and control section.

[0037] like Figure 2 As shown in the figure, 11 is the cutterhead, and the rear of the cutterhead 11 is the shield. The slurry preparation part of the intelligent injection system for thick slurry of the present invention mainly includes: a dry powder slurry tank 21, a dry powder weighing sensor 22 is installed at the bottom of the dry powder slurry tank 21, and the dry powder slurry tank 21 is connected to the slurry tank 26 through an aggregate conveying system; the aggregate conveying system includes a horizontal screw conveyor 24 and an inclined screw conveyor 25, the dry powder slurry tank 21 is connected to the inlet of the horizontal screw conveyor 24 through the discharge valve 23, and the aggregate is conveyed to the slurry tank 26 through the horizontal screw conveyor 24 and the inclined screw conveyor 25; a B liquid tank 27 containing coagulant is connected to the slurry tank 26 through a B liquid conveying pump 28 and corresponding pipelines, and a slurry tank discharge control valve 29 is installed at the discharge port of the slurry tank 26.

[0038] The mixed aggregate enters the conveying system in the dry powder slurry tank 21 under the control of the discharge valve 23, and is conveyed to the slurry tank 26 by the corresponding screw conveyor of the conveying system. The weight of the aggregate delivered to the slurry tank 26 can be measured by the weighing sensor 22. The coagulant enters the slurry tank 26 under the pumping of the B liquid delivery pump 28. The amount of B liquid (coagulant) delivered to the slurry tank 26 can be calculated by calculating the working time or revolutions of the slurry tank 26, thereby realizing the controllable preparation of thick slurry.

[0039] The grouting pipeline system of the intelligent injection system for thick slurry of the present invention mainly includes: main grouting pipeline 30, front shield grouting pipeline 32 and tail shield grouting pipeline 31.

[0040] The discharge pipe of the slurry tank 26 is connected to the main grouting pipe 30, and a discharge control valve 29 is installed on the discharge pipe; the tail shield grouting pipe 31 is branched off from the main grouting pipe 30 and connected to the tail shield grouting port 312, which is set on the tail shield shell and injects thick slurry between the tail shield shell and the tunnel wall. The tail shield grouting ports 312 are evenly arranged around the outer circumference of the tail shield; the number of tail shield grouting ports 312 in the outer annular direction can be adjusted according to the diameter of the shield body, and the number of tail shield grouting ports 312 in the axial direction can be adjusted according to the axial dimension of the tail shield. In the figure, three tail shield grouting ports 312 are set in the same column in the axial direction of the tail shield.

[0041] The tail shield grouting pipeline 31 is connected to the tail shield grouting port 312 via the tail shield grouting pipe 311 corresponding to the grouting port. A grouting control pneumatic ball valve 33 is installed on the tail shield grouting pipeline 31, and a one-way valve 34 and a manual ball valve 35 facing the grouting port are installed on the tail shield grouting pipe 311 in sequence.

[0042] Specifically, several tail shield grouting pipelines 31 are evenly branched off from the main grouting pipeline 30 along the radial direction of the shield body. Each tail shield grouting pipeline 31 branches off from several tail shield grouting pipes 311. The tail shield grouting ports 312 connected to the tail shield grouting pipes 311 branched off from the same tail shield grouting pipeline 31 are distributed in the same axial direction on the outer periphery of the tail shield shell.

[0043] The main grouting pipeline 30 is also branched off into a front shield grouting pipeline 32, which is connected to a front shield grouting port 322 located on the front shield shell and injecting thick grout between the front shield shell and the tunnel wall. The front shield grouting ports 322 are evenly arranged around the outer circumference of the front shield. Similarly, the number of front shield grouting ports 322 in the outer annular direction can be adjusted according to the shield diameter, and the number of front shield grouting ports 322 in the axial direction can be adjusted according to the axial dimension of the front shield. In the figure, three front shield grouting ports 322 are arranged in the same column in the axial direction of the front shield.

[0044] The front shield grouting pipeline 32 is connected to the front shield grouting port 322 via the front shield grouting pipe 321 corresponding to the front shield grouting port 322. A grouting control pneumatic ball valve 33 is installed on the front shield grouting pipeline 32, and a one-way valve 34 and a manual ball valve 35 facing the grouting port are installed sequentially on the front shield grouting pipe 321.

[0045] Specifically, several front shield grouting pipelines 32 are evenly branched off from the main grouting pipeline 30 along the radial direction of the shield body. Several front shield grouting pipes 321 are branched off from each front shield grouting pipeline 32. The front shield grouting ports 322 connected to the front shield grouting pipes 321 branched off from the same front shield grouting pipeline 32 are distributed in the same axial direction on the outer periphery of the front shield shell.

[0046] Furthermore, the front shield grouting port 322 and the tail shield grouting port 312 are arranged in a group on the same straight line along the shield body axis of the front shield shell and the tail shield shell.

[0047] As another implementation, if increased costs are permissible, a middle shield grouting port can be further provided on the middle shield at a position on the same axial straight line as the front shield grouting port 322 and the tail shield grouting port 312. The middle shield grouting port is connected to the main grouting pipeline through a corresponding middle shield grouting pipeline. Adding a middle shield grouting port can make grouting in the axial direction more uniform.

[0048] A hydraulic grouting pump 39 is installed on the main grouting pipeline 30 between the connection of the discharge pipeline of the slurry tank 26 and the connection of the tail shield grouting pipeline 31 and the front shield grouting pipeline 32. The discharge pipeline of the slurry tank 26 is located upstream of the pumping direction of the grouting pump, and the tail shield grouting pipeline 31 and the front shield grouting pipeline are located downstream of the pumping direction of the grouting pump.

[0049] A flushing pipe section is reserved at one end upstream of the slurry flow in the main grouting pipeline 30 (i.e., after the connection of the discharge pipe of the slurry tank 26). The flushing pipe section is used to connect a clean water source to flush the entire grouting pipeline. The flushing pipe section is equipped with a cleaning water control valve 38 and a flushing check valve 37 facing the flushing direction in sequence along the flushing water flow direction.

[0050] A flushing and discharge pipe section is reserved at one end downstream of the grout flow in the main grouting pipeline 30 (after the connection of the front shield grouting pipeline 32). The flushing and discharge pipe section is used to discharge the residual flushing water in the grouting pipeline. A cleaning water discharge valve 36 is installed on the flushing and discharge pipe section.

[0051] The detection and control section includes a PLC controller 40 as the control core, as well as shield grouting pressure sensors 41, a hydraulic control section 42, and excavation chamber earth pressure sensors 43, all electrically connected to the PLC controller 40. The shield grouting pressure sensors 41 are respectively installed on the front shield shell in front of the front shield grouting port 322 (towards the cutterhead 11) and on the middle shield shell, with multiple sensors evenly distributed in the circumferential direction of the shield according to the shield diameter.

[0052] Furthermore, the grouting pressure sensors 41 on the front and middle shields are arranged in groups along the same straight line on the front and middle shield shells along the shield's axial direction, and are spaced apart from the front shield grouting port 322 and the tail shield grouting port 312 in the circumferential direction of the shield, as shown in Figures 3(a) and 3(b). The difference between Figures 3(a) and 3(b) is whether the top and bottom of the shield are grout injection holes (grouting holes) or pressure sensors.

[0053] As another implementation, if increased costs are permissible, a tail shield pressure sensor can be further installed on the tail shield at a position on the same axial line as the front shield pressure sensor and the middle shield pressure sensor. The tail shield pressure sensor can be used to monitor the grouting pressure at the tail shield during the grouting process.

[0054] The PLC controller 40 monitors the soil and water pressure in the excavation chamber in real time via the excavation chamber soil pressure sensor 43, and monitors the soil and water pressure in the front and middle shields in real time via the shield grouting pressure sensor 41. The hydraulic control unit 42 is connected to a hydraulic oil source 421 at one end. A hydraulic proportional speed control valve is installed on the intermediate pipeline connecting to the hydraulic drive motor of the hydraulic grouting pump 39, and a switching valve is installed on the intermediate pipeline connecting to the pneumatic control valve. The PLC controller 40 controls the speed of the hydraulic grouting pump 39 via the hydraulic proportional speed control valve, thereby controlling the injection speed of the thick grout, and also controls the on / off state of the pneumatic control valve on the slurry pipeline via the switching valve.

[0055] The shield shell thick slurry injection system of the present invention can realize the shield shell thick slurry injection method of the present invention, and the specific method will be described in detail in the following method embodiments.

[0056] Method Implementation Examples: This invention discloses a method for injecting thick grout into the shield shell of a tunnel boring machine (TBM). The thick grout injected into the shield body is composed of a mixture of liquid A (mixed aggregate) and liquid B (coagulant), possessing characteristics such as high viscosity and strong water-retaining properties. During normal TBM tunneling, this invention monitors the soil and water pressure in the excavation chamber (i.e., the soil chamber) and the front and middle shield bodies in real time. The soil and water pressure at the front and middle shield bodies reflects the grouting pressure at the corresponding locations. The soil and water pressure in the excavation chamber is detected by soil pressure sensors on the partition plates, while the soil and water pressure at the front and middle shields is detected by pressure sensors installed on the front and middle shields according to this invention. The key concept of this invention is that it does not detect the grouting pressure at the injection holes, because the pressure at injection holes is generally higher than the pressure at locations far from the injection holes. Instead, this invention detects the pressure in the outer annular cavity of the shield body between the two injection holes. Because the thick grout has a certain degree of fluidity, this invention places the sensors on the shield body between the two injection holes.

[0057] Specifically, for the pressure sensors on the front and middle shields along the same axis, if the pressure sensor at a certain point on the middle shield reaches the target value, the injection holes on the front and tail shields located below the pressure sensors that have reached the target value are closed simultaneously. If a pressure sensor on the front shield reaches the target value while the pressure sensor on the middle shield in the same axis does not, then the injection hole below that pressure sensor on the front shield is closed, and the corresponding injection hole on the tail shield continues to inject. If the pressure sensors of both the front and middle shields along the same axis fail to reach the target value, grouting will continue.

[0058] The specific location of the injection hole can be determined based on the shape of the tunnel boring machine, the tunneling conditions, and the simulation of the thick slurry.

[0059] As shown in Figure 3(a), when there are injection holes at the top and bottom of the shield, the bottom injection hole closes when all pressure sensors adjacent to it reach the target value. For the top injection hole, the top injection hole closes when both pressure sensors adjacent to it reach the target value. The control for other points is as follows: when a pressure sensor at a certain point reaches the target value, the adjacent lower injection point closes, and when the last pressure sensor reaches the target value, all injection holes stop injecting.

[0060] For the case shown in Figure 3(b) where there are pressure sensors at the top and bottom, the injection hole between the two sensors is closed when both the bottom pressure sensor and its adjacent sensor reach the target value. The control for other points is as follows: when a pressure sensor at a certain point reaches the target value, its adjacent lower injection point is closed, and when the last pressure sensor reaches the target value, all injection holes stop injecting.

[0061] For setting the target value, the pressure sensors at each point on the shield should be calibrated online or offline with earth pressure sensors at similar heights to obtain a suitable reference deviation value (to ensure that grouting does not enter the soil chamber). At the same time, under the premise of meeting the safety of the tunneling parameters, the target value of the pressure sensors on the middle shield should be slightly higher than that of the front shield in the same group (i.e., the same axis).

[0062] When it is necessary to correct the attitude of the tunnel boring machine, the pressure in each section of the ring cavity can be controlled by increasing or decreasing the target value of the pressure sensor at a certain point during the injection of thick slurry, which helps to correct the attitude.

[0063] The method of this invention controls the amount of grout injected into the back of the shield body by comparing the soil chamber pressure and the grouting pressure, thereby achieving intelligent injection. The specific grouting process is as follows: 1. Pulping process.

[0064] When the equipment begins tunneling, the thick slurry preparation system, such as that described in the slurry preparation section of the system embodiment, installed on the tunnel boring machine trailer begins slurry preparation. The slurry preparation process can be automatically batched, prepared, and transported by the slurry control system. The dry powder slurry tank 21 is matched with the tunnel material train to store the dry powder slurry. The aggregate in the dry powder slurry tank 21 is transported to the slurry tank 26 through the discharge valve 23 and the conveying screw system. At the same time, the B liquid in the coagulant B liquid tank 27 is transported to the slurry tank 26 through the B liquid transfer pump 28. After the two slurries are fully mixed in the slurry tank, the grouting operation is carried out by the hydraulic grouting pump 39.

[0065] The ratio of the grouting slurry can be adjusted by the weighing sensor 22 on the dry powder slurry tank 21 and the B liquid delivery pump 28 to establish better slurry test performance. At the same time, the cumulative amount of dry powder and coagulant B liquid can be calculated and recorded.

[0066] 2. Grouting process.

[0067] The grouting process of thick mud is achieved by hydraulic grouting pump 39. To adapt to different tunneling speeds and soil and water pressures, the thick mud injection can be adaptively matched through the "pressure + speed" control logic.

[0068] 1) When the water and soil pressure in the soil chamber changes or the grouting pressure is close to the water and soil pressure in the soil chamber at the same height, the water and soil pressure in the soil chamber at the same height is taken as the target value of the grouting pressure at the same height (a reference deviation value can be preset according to the pipeline characteristics). The output speed of the hydraulic grouting pump 39 is adjusted by the PLC controller, thereby realizing the automatic control of the grouting pressure of the thick mud system.

[0069] The target value of soil and water pressure is the soil and water pressure value inside the soil chamber detected by the soil chamber pressure sensor installed on the partition plate. The grouting pressure sensor installed on the shield body should be interlocked with the preset reference deviation value of the detection value of the grouting pressure sensor at the same or adjacent horizontal height on the partition plate. The pressure sensors installed on the front shield and the middle shield are all on the same axis (that is, at the same horizontal height).

[0070] The specific control method is as follows: A grouting pump delivers mixed grout, and the grouting control pneumatic ball valve 33, one-way valve 34, and manual ball valve 35 on the shield body inject thick grout into the gap between the shield body and the soil layer to prevent settlement. To better and faster form a dense annular cavity, thick grout is injected into both the front and tail shields, but pressure sensors are installed on the middle and front shields. The pressure sensor on the front shield and its injection hole are at a certain axial distance in the tunneling direction. The radial installation position of the pressure sensor matches that of the soil chamber pressure sensor, i.e., at the same or similar vertical height, so that the pressure in the detection section and the soil chamber pressure can be interlocked to prevent the water and soil pressure in the detection section from exceeding the water and soil pressure at the corresponding height in the soil chamber, which would cause the mixed grout to enter the soil chamber.

[0071] The radial installation position of the pressure sensor on the shield body is also the radial position of the tunneling machine. Matching the radial installation position of the pressure sensor on the shield body with the soil chamber pressure sensor means that the pressure sensor on the shield body and the soil chamber pressure sensor are at the same or similar radial positions on the tunneling machine. This also ensures that the pressure sensor on the shield body and the soil chamber pressure sensor are at the same or similar vertical height. The soil chamber pressure sensor can be designed with a reasonable installation position on the partition plate according to the actual working conditions. The pressure sensor installed on the shield body is set between the two injection holes, and its height or radial position is close to that of the soil chamber pressure sensor. The interlocking of the pressure sensors involves setting the target value of the pressure sensor on the shield body to be near the soil chamber pressure value obtained by the soil chamber pressure sensor in a similar radial position. This interlocking is based on the setting of a reference deviation value, which is obtained based on relevant calculations and empirical values.

[0072] Specifically, for each monitoring point, when the grouting pressure at the middle shield position, as monitored by the shield grouting pressure sensor 41 located at the middle shield position, reaches the target set value (set according to the corresponding earth chamber pressure, slightly higher than the target value at the front shield position on the same axis), the pneumatic control valves of the grouting pipelines corresponding to the grouting holes of the front and tail shields adjacent to the monitoring point in the height direction and located below the monitoring point are closed; the grouting pipeline system in the corresponding system embodiment is to close the grouting control pneumatic ball valves 33 on the tail shield grouting pipeline 31 of the tail shield grouting hole located below the shield body axial line where the shield grouting pressure sensor 41 located at the middle shield position is located when the pressure reaches the set value, and the front shield grouting pipeline 32 of the front shield grouting hole, stopping the injection of grout from the grouting holes adjacent to the monitoring point in the axial line.

[0073] When the grouting pressure of the middle shield reaches the target value, the grouting of the front and tail shields at the corresponding positions is stopped. This can prevent grout from entering the soil chamber as much as possible. Even if the grouting pressure of the front shield is insufficient at this time, during the subsequent tunneling process, as the shield body advances, the original grouting position of the front shield will become the middle shield position. At this time, grouting will continue until the grouting pressure of the middle shield position is satisfied, thus achieving the purpose of intelligent injection to prevent settlement.

[0074] When the grouting pressure of the front shield reaches the target set value (based on the corresponding earth chamber pressure) as monitored by the grouting pressure sensor 41 located at the front shield position, but the grouting pressure of the middle shield on the same axis has not yet reached the corresponding set value, the pneumatic control valve (e.g., the grouting control pneumatic ball valve 33 on the front shield grouting pipeline 32) of the front shield grouting hole at the adjacent monitoring point in the height direction that is simultaneously lower than the target set value is closed. In the corresponding system embodiment, the grouting pipeline system is to close the grouting control pneumatic ball valve 33 on the front shield grouting pipeline 32 of the front shield grouting hole located below the shield body axial line where the grouting pressure sensor 41 located at the front shield position reaches the set value, stop the injection of grout from the front shield grouting hole adjacent to the monitoring point in the axial line, and continue to inject grout from the corresponding tail shield grouting hole until the corresponding middle shield grouting pressure reaches the set value.

[0075] If the grouting pressure at the front shield position reaches the set value, but the grouting pressure at the corresponding middle shield position does not reach the target value, grouting at the corresponding front shield position will stop to prevent thick grout from entering the soil chamber. Grouting will continue at the corresponding tail shield grouting hole until the middle shield position reaches the target grouting pressure. While the tail shield continues grouting, the front shield has already reached a pressure higher than the tail shield's target pressure, preventing grout from the tail shield from advancing into the soil chamber. Simultaneously, the pressure at the front shield causes a dense annular cavity to form at the middle shield during grouting, achieving the purpose of intelligent injection to prevent settlement.

[0076] It should be noted that the number of sensors and slurry injection paths shown in the diagram should be adjusted and matched according to the diameter of the tunnel boring machine.

[0077] In summary, this invention arranges pressure sensors and grouting holes at intervals along the circumference of the shield body. During grouting, the target value of the pressure sensor is set to the detection value of the soil chamber pressure sensor closest in radial position, i.e., the pressure at a similar height in the soil chamber is used as the target value of the shield pressure sensor to prevent injected grout from entering the soil chamber. Simultaneously, when the grouting pressure of the front shield detected by the current shield pressure sensor reaches the corresponding target value, grouting of the front shield grouting hole adjacent to the sensor below it is stopped. Grouting of the middle and tail shields continues if the grouting pressure has not been reached. To save costs, this invention only sets pressure sensors and grouting holes in the middle and front shields. Therefore, when the pressure of the front shield reaches the target but the pressure of the middle shield has not, grouting continues in the tail shield. When the grouting pressure of the middle shield reaches the target value, grouting in the front and tail shield grouting holes adjacent to the sensor below it stops. When all the middle shield pressure sensors along the outer circumference of the shield body reach the target set value, grouting in all grouting holes stops.

[0078] 2) When the tunneling speed of the tunnel boring machine changes, the injection time to reach the target value can be set according to the working conditions. For example, the output speed of the thick grout of the hydraulic grouting pump 39 can be automatically matched and adjusted by adjusting the proportional speed control valve of the hydraulic control part 42 through the PLC controller 40, so as to achieve the overall matching of the grouting speed and the tunneling speed and realize the purpose of intelligent grout injection.

[0079] 3. Cleaning process When the thick grouting process of the shield body is completed and the grouting operation is stopped, the grouting pipeline needs to be cleaned. Taking the grouting pipeline system described in the system embodiment as an example, when the hydraulic grouting pump 39 stops working, the discharge valve 23, which serves as the material discharge control valve of the grouting tank, and the grouting control pneumatic ball valve 33 on the shield body grouting pipeline automatically close, and the cleaning water control valve 38 automatically opens. External cleaning water automatically and promptly cleans the grouting pipeline through the flushing check valve 37, and discharges the cleaning water to the equipment sewage tank or slag discharge belt through the cleaning water discharge valve 36. The cleaning water flushing time can be set after each grouting is completed. When the set time is reached, the cleaning water control valve 38 automatically closes and stops the cleaning, realizing intelligent flushing of the grouting pump and pipeline.

[0080] In the system embodiment, pressure sensors are installed only on the shield shells of the front and middle shields. In other embodiments, pressure sensors can also be installed on the tail shield as auxiliary parameters to more intuitively observe the pressure changes between the shield and the soil, ensuring the pressure safety between the shield and the soil. Considering cost, the installation of pressure sensors on the tail shield can also be omitted.

[0081] As an alternative implementation, pressure sensors can also be installed on each injection pipeline of the shield body as auxiliary control parameters to more intuitively observe the pressure changes between the shield body and the soil, ensuring the pressure safety between the shield body and the soil. Considering cost, the installation of the tail shield pressure sensor can also be omitted.

[0082] In the system implementation, a shared pneumatic control valve for controlling the corresponding grouting holes in the same group was used only on the front shield grouting pipeline and the tail shield grouting pipeline. Alternatively, independent pneumatic control valves could be installed on the grouting pipes corresponding to each grouting hole to more accurately detect the injection pressure and control the opening and closing of the injection holes. Another implementation could be to install flow meters to collect grout injection volume at each point, accumulating construction data for system optimization.

[0083] The shield shell thick slurry injection method and corresponding system of this invention can intelligently adjust the grouting volume according to the water and soil pressure and the advance speed to match the changes in tunneling speed and water and soil pressure. This solves the problem in the prior art that it cannot accurately judge and control the amount of grouting based on the pressure between the shield and the soil. Therefore, this solution can ensure the intelligent preparation and intelligent injection of thick slurry during the normal tunneling process of the shield machine, making the tunneling work safer and more intelligent, improving the accuracy of slurry injection volume, and effectively reducing the construction risks such as settlement, water inrush, sudden attitude changes, and shield jamming when the shield machine passes through.

Claims

1. A method for injecting thick slurry into the shield shell of a tunnel boring machine, characterized in that, The front shield shell is circumferentially spaced with front shield pressure sensors, and the middle shield shell is circumferentially spaced with middle shield pressure sensors. Front shield grouting ports are circumferentially spaced with front shield grouting ports, and tail shield grouting ports are circumferentially spaced with tail shield grouting ports. The front and middle shield pressure sensors are grouped together on the same straight line along the shield's axial direction on the front and middle shield shells, and are alternately arranged with the front and tail shield grouting ports on the same straight line along the shield's axial direction. The grouting pressure between the middle and rear sections of the shield and the soil layer is collected by the middle shield pressure sensors, and the pressure is also collected by the front shield pressure sensors. The grouting pressure between the front part of the shield body and the soil layer is controlled. If the grouting pressure in the middle and rear parts and the front part do not reach the grouting pressure target, grouting is carried out through the grouting ports of the front shield and the tail shield. If a front shield pressure sensor reaches the corresponding grouting pressure target, but the pressure sensor of the middle shield in the same group does not reach the corresponding grouting pressure target, the grouting port of the front shield adjacent to the lower part of the front shield pressure sensor in the circumferential direction is closed, and grouting is carried out only through the tail shield grouting port in the same group as the front shield grouting port. If a middle shield pressure sensor reaches the corresponding grouting pressure target, the grouting ports of the front shield and the tail shield adjacent to the lower part of the middle shield pressure sensor in the circumferential direction are closed at the same time.

2. The method for injecting thick slurry into the shield shell of a tunnel boring machine according to claim 1, characterized in that, The grouting pressure target is set based on the soil chamber pressure at the same vertical height as the corresponding grouting pressure collection point.

3. The method for injecting thick slurry into the shield shell of a tunnel boring machine according to claim 2, characterized in that, The grouting pressure target of the middle shield pressure sensor is set based on the soil chamber pressure at the same vertical height position, and is higher than the grouting pressure target of the front shield pressure sensor in the same group.

4. The method for injecting thick slurry into the shield shell of a tunnel boring machine according to claim 1, characterized in that, When there are grouting ports at the top and bottom of the shield, the bottom grouting port is closed when the pressure sensors adjacent to the bottom grouting port reach the target value; when the two pressure sensors adjacent to the top grouting port reach the target value, the top grouting port is closed; when there are pressure sensors at the top and bottom of the shield, the grouting port between the two pressure sensors is closed when the bottom pressure sensor and its adjacent pressure sensor reach the target value.

5. The method for injecting thick slurry into the shield shell of a tunnel boring machine according to claim 1, characterized in that, The front shield pressure sensor is located on one side of the cutterhead at the front shield grouting port and at a certain axial distance from the front shield grouting port.

6. The method for injecting thick slurry into the shield shell of a tunnel boring machine according to claim 1, characterized in that, When the tunneling speed of the tunnel boring machine changes, the output speed of the thick grout in the grouting pipeline is adjusted according to the pre-calibrated correspondence.

7. A thick slurry injection system for the shield shell of a tunnel boring machine, characterized in that, The system includes a grout preparation unit for preparing a thick grout for filling the gap between the shield body and the tunnel wall, a grouting pipeline system connected to the grout preparation unit for transporting the thick grout, and a detection and control unit. The grouting pipeline system includes front shield grouting ports spaced circumferentially on the front shield shell, tail shield grouting ports spaced circumferentially on the tail shield shell, and valves for controlling the opening and closing of the front and tail shield grouting ports. The detection and control unit includes front shield pressure sensors spaced circumferentially on the front shield shell, and middle shield pressure sensors spaced circumferentially on the middle shield shell. The front and middle shield pressure sensors are grouped and arranged on the same straight line along the shield body axis on the front and middle shield shells, and alternate with the front and tail shield grouting ports spaced on the same straight line along the shield body axis on the shield body circumferentially. The shield shell grout injection system of the tunnel boring machine is used to: collect the grouting pressure between the middle and rear parts of the shield and the soil layer through the middle shield pressure sensor, and collect the grouting pressure between the front part of the shield and the soil layer through the front shield pressure sensor; if neither the middle and rear grouting pressure nor the front grouting pressure reaches the grouting pressure target, grouting is carried out through the grouting ports of the front shield and the tail shield; if a front shield pressure sensor reaches the corresponding grouting pressure target, but the middle shield pressure sensor in the same group does not reach the corresponding grouting pressure target, the lower front shield grouting port adjacent to the previous front shield pressure sensor is closed, and grouting is carried out only through the tail shield grouting port in the same group as the previous front shield grouting port; if a middle shield pressure sensor reaches the corresponding grouting pressure target, the lower front shield grouting ports adjacent to this middle shield pressure sensor in the same group are closed simultaneously.

8. The shield shell thick slurry injection system for tunnel boring machines according to claim 7, characterized in that, The grouting pressure target is set based on the soil pressure at the same vertical height position as the corresponding grouting pressure acquisition point. The grouting pressure target of the middle shield pressure sensor is higher than that of the front shield pressure sensor in the same group.

9. The shield shell thick slurry injection system for tunnel boring machines according to claim 8, characterized in that, When there are grouting ports at the top and bottom of the shield, the bottom grouting port is closed when the pressure sensors adjacent to the bottom grouting port reach the target value; when the two pressure sensors adjacent to the top grouting port reach the target value, the top grouting port is closed; when there are pressure sensors at the top and bottom of the shield, the grouting port between the two pressure sensors is closed when the bottom pressure sensor and its adjacent pressure sensor reach the target value.

10. The shield shell thick slurry injection system for tunnel boring machines according to claim 8, characterized in that, The front shield pressure sensor is located on one side of the cutterhead of the front grouting hole and at a certain axial distance from the front grouting hole.

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