[0041] like Figure 1 to Figure 7 As shown in the figure, a new method of tunnel excavation of the present invention is carried out by cutting and excavating along the outer circumference of the face 9 through a frame-shaped drilling tool 4 located at the front end of the cylindrical excavation device, and simultaneously adjusting and excavating the soil body cut into the excavation device, for tunnel excavation. The soil body cut into the tunneling device is at the rear end side of the tunneling direction, and the axial stress is applied forward by the stress applying device to form a soil plug that promotes the stability of the face 9; during the tunneling, the rear end of the soil plug is opened. unearthed. Specifically include the following steps:
[0042] Step 1, site preparation;
[0043] In this step, in addition to hardening the site and ensuring that the site-related hard conditions meet the construction requirements, a reasonable equipment installation plan should be formulated according to the size of the site (especially in the hole or other relatively narrow construction sites).
[0044] Step 2: Assembling, debugging and positioning of the excavation device;
[0045] 2.1. Install each part of the tunneling device according to the installation instructions;
[0046] 2.2. After the installation is completed, start the equipment to check and debug the working state of the drilling tool, the tunneling function of the tunneling device, the direction adjustment function, the soil cutting function, the stress application function, etc.;
[0047] 2.3. According to the tunnel axis and technical disclosure requirements, adjust the position of the excavation device and the posture of entering the soil, such as figure 1 shown;
[0048] Step 3, cutting and excavation;
[0049] While the frame-shaped drilling tool 4 is cutting and excavating along the outer circumference of the face 9, the internal pressure of the soil plug is monitored in real time, and the internal pressure of the soil plug is controlled within the range of 0.99-1.5 times the soil pressure of the face 9. Continuous adjustment of excavation to achieve excavation, such as figure 2 shown.
[0050] Specifically include the following steps:
[0051] 3.1. Start the tunneling device. With the continuous cutting of the frame-shaped drilling tool 4, the tunneling device gradually penetrates into the tunnel face 9, and the soil in front of the tunnel face 9 gradually enters the tunneling device;
[0052]3.2. The soil entering the tunneling device forms a soil plug under the blocking of the stress applying device;
[0053] 3.3. Adjust the excavation rate by monitoring the pressure around the soil plug, and control the standard internal pressure of the soil plug to be 0.99-1.5 times the soil pressure on the face 9 while the excavation and excavation are carried out simultaneously; the specific control method is as follows :
[0054] 3.3.1. Along the excavation direction, the internal pressures of the soil plugs from front to back are P1, P2 and P3 respectively. Among them, P1 near the tunnel face is identified as the soil pressure on the tunnel face, P2 is the standard internal pressure of the soil plug, and P3 is the unearthed soil pressure. The internal pressure of the soil plug, in the stable state of the face, the relative relationship between the three is: P2>P1, P3
[0055] Among them, P1, P2, P3 are a single value or a sequence of numbers;
[0056] Here, P1 is the internal pressure of the soil plug within 1m from the tunnel face in the axial direction of the tunnel. Specifically, it is obtained by monitoring and calculation of the soil pressure sensor set at the front end within 1m from the tunnel face, because it is closer to the tunnel face. , P1 is the soil pressure on the face; P3 is the internal pressure of the soil plug in the excavated section of the soil plug, which is obtained through monitoring and calculation by the earth pressure sensor set at the rear end within 1m from the excavated surface of the soil plug; P2 is the soil pressure set at P1 , P3 corresponds to the standard value of the soil plug internal pressure obtained by the monitoring and calculation of the soil pressure sensor in the middle section between the soil pressure sensors;
[0057] 3.3.2. When 0.7P1≤P2<0.99P1, adjust the stress application degree of the stress application device and apply pressure to the soil plug, so that P2 gradually increases and finally becomes larger than P1;
[0058] 3.3.3. When 0.5P1≤P2≤0.8P1 or when the adjustment effect by adjusting the stress application device is not obvious, increase the excavation speed, and increase the pressure in the plug by increasing the amount of jacked soil, so that P2 is eventually greater than P1 ;
[0059] 3.3.4. When P3>P2, increase the unearthed speed and the unearthed quantity, so that P3 gradually decreases and finally becomes smaller than P2.
[0060] In this construction method, when the stratum conditions are good, the stability of the face 9 and the surrounding rock in front can be basically achieved by stabilizing the soil body entering the tunneling device.
[0061] For the surrounding rock with poor stratum conditions, when the soil plug pressure is difficult to balance with the water and soil pressure in the face 9 and the stratum, the soil body entering the tunneling device is subjected to axial force through the soil stress applying device during the excavation. The soil in the tunneling device forms a "soil plug" under the action of axial stress, so that the pressure of the soil plug and the pressure of the soil body on the face 9 are balanced, thereby keeping the face 9 stable.
[0062] Step 4. Lining installation;
[0063] When a certain depth is excavated, a cavity of a certain length is generated at the end of the excavation device, and the lining construction is carried out under the protection of the excavation device.
[0064] Step 5, cycle step 3-step 4, until all the tunnel construction is completed.
[0065] The excavation device used in the above-mentioned tunnel excavation method includes an earth bin 1 at the front end in the excavation direction, a power bin in the middle section, and a lining bin at the tail end. The power bin is equipped with a soil cutting control system, a soil bin 1 propulsion system, and a direction adjustment system. The soil bin 1 propulsion system is a number of oil cylinders that are arranged around the power bin at intervals, mainly used to promote the excavation of the soil bin 1. The direction adjustment system is mainly It includes a deviation correction system and a measurement system. The deviation correction system mainly changes the trajectory of the excavation device through the deviation correction cylinder, and activates the corresponding deviation correction cylinder according to the adjustment target of the excavation device trajectory until the attitude adjustment is completed. The system setting of the same function in the conventional shield machine can be consistent; the structure of the lining silo is the same as that in the conventional shield machine.
[0066] When the pipe jacking method is required, the propulsion system of the soil bin 1 of the power bin needs to be adjusted to the rear of the lining bin at the rear end.
[0067] like image 3 As shown, the soil bin 1 is a hollow cylindrical structure with an open front end. The front end face is provided with a frame-shaped drilling tool 4 along the circumferential direction, and the rear end is provided with a stress applying device and an automatic slag discharging device 7. There is an earth pressure monitoring system to monitor the pressure of the soil in the soil bin 1 .
[0068] The axial length of the soil bin 1 is 0.5-2 times the diameter of the tunnel, and the vertical section is consistent with the tunnel face 9 . When necessary, the length of the soil bin 1 can be appropriately increased to stabilize the face 9 . The front end of the soil bin 1 is not specifically limited, it can be a flat vertical surface or a wedge surface treatment, and the front end shape can be a circle, a square, a horseshoe shape or a special-shaped structure. In order to further reduce the driving resistance, such as image 3 As shown, the front soil bin 1 is a special-shaped structure, and the whole is set on a wedge-shaped end surface with the top protruding forward. The two sides gradually form an arc from the central position to the inside of the bin body and transition to the bottom, and are connected to form a zipper-shaped bottom end concave. shaped end.
[0069] The frame-shaped drilling tool 4 is a cutting drilling tool arranged along the circumference of the front end face of the soil bin 1 to directly contact the soil body of the face 9 for cutting, so as to reduce the resistance of jacking and the required power. The frame-shaped drilling tool 4 can be a continuous flexible drilling tool, such as image 3 As shown, it can also be rigid drilling tools arranged at intervals along the circumference of the end face, such as Figure 5 As shown, a combination of flexible drilling tools and rigid drilling tools is also possible.
[0070] The flexible drilling tools are arranged circumferentially along the front end of the soil bin 1, and the flexible drilling tools are wire saws or assembled from several short drill pipe joints, chain cutters or universal joints through several joints. like image 3 and 4 As shown, the flexible drilling tool is connected by universal joints with external helical blades, and is arranged on the end face of the front end of the soil bin 1 along the circumferential direction, and its cutting rate is controlled by the soil cutting control system of the power bin. The cutting soil can enter the inner cavity of the soil bin 1 shell and be discharged in the shell, or directly enter the bin body and be discharged together with the soil plug through the automatic slag discharging device 7 in the soil bin 1 .
[0071] Rigid drilling tools are mainly one or more of scrapers, pick bits, three-blade drill bits, and compound drill bits, down-the-hole hammers, but are not limited to the above-mentioned types. like Figure 5 As shown, the rigid drilling tool is a down-the-hole hammer head, which is arranged at intervals along the circumferential direction, and the spacing distance is not greater than 0.5m.
[0072] The choice of drilling tool type mainly depends on the formation conditions. When the surrounding rock geology in front of the face 9 is uniform and mainly consists of soil layers and sand layers, flexible drilling tools are mainly used. Arranged at the end of soil bin 1 at a certain distance. If the surrounding rock of the face 9 is soft on the top and hard on the bottom, the upper part of the end of the soil bin 1 is provided with a flexible drilling tool, and the lower part is a rigid drilling tool.
[0073] In addition, the distribution and shape of the drilling tools are related to the shape of the end of the soil bin 1. For example, when the shape of the end of the soil bin 1 is round or square, the drilling tools can be made of integral flexible drilling tools or assembled flexible drilling tools (the formation is relatively Soft case) or rigid drilling tool assembly (hard formation), for example, when the shape of the end of soil bin 1 is a special-shaped structure, the drilling tool can only be assembled flexible drilling harder case).
[0074] A protective sleeve can also be provided outside the cutting drill, and the cutting drill is embedded in the protective sleeve to ensure the safety and stability of the drilling tool.
[0075] The stress applying device is arranged at the rear end of the soil bin 1 of the tunneling device, and includes a stress baffle 51 and a jacking system 52 for retracting and pulling the stress baffle 51. The retracting state and pushing out of the retractable stress baffle 51 are adjusted through the jacking system 52. Then adjust the soil pressure in the soil bin 1, and finally achieve a balance between the pressure of the soil plug and the pressure of the face 9. The stress baffles 51 are arranged symmetrically on the left and right sides in the vertical section of the soil bin 1, and one side edge is attached to and hinged with the inner wall of the soil bin 1. The maximum horizontal width of the stress baffle 51 is smaller than the horizontal width of the longitudinal section of the soil bin 1. The 1/2 setting, that is, the setting between the two stress baffles 51 is not closed or in contact, and an opening is always left open for excavation. A pusher system 52 is provided on the side of the stress baffle plate 51 facing away from the palm surface 9 . In this embodiment, the pusher system 52 is a telescopic oil cylinder.
[0076] The automatic slag removal device 7 includes a soil conveying device and a driving system. The soil conveying device includes a conveying outer casing and a conveying drilling tool, and is arranged horizontally or inclined upward at the bottom of the soil bin 1. In general, it is enough to be located in the same vertical section as the fixed side of the stress application device. If the stratum is viscous, its front end can exceed the fixed side of the soil stress application device. The drive system is located in the power compartment, and the excavation speed and excavation volume are adjusted according to the soil pressure monitoring data.
[0077] One or more sets of soil conveying devices are generally set up, and the number is flexibly adjusted according to the size of the tunnel section and the stratum conditions. When the tunnel section is large or the soil is difficult to discharge, multiple sets are set up and evenly distributed at the bottom of the soil bin 1. When the section is small or the soil is discharged quickly, one set can be set at the bottom of the soil bin 1.
[0078] The type of soil conveying device is not specifically limited, it can be a screw conveying device, which discharges the soil in the soil bin 1 and transfers the slag in combination with the slag conveying device, and the type can be selected according to the geological conditions of the stratum.
[0079] The internal pressure of the soil plug is monitored in real time by the earth pressure monitoring system to ensure construction safety and guide construction.
[0080] P1 is the internal pressure of the soil plug within 1m from the tunnel face in the axial direction of the tunnel. Specifically, it is obtained by monitoring and calculation of the soil pressure sensor at the front end within 1m from the tunnel face. Because it is close to the tunnel face, it is determined that P1 is the soil pressure on the face; P3 is the internal pressure of the soil plug in the excavated section of the soil plug, which is obtained through monitoring and calculation by the earth pressure sensor set at the rear end within 1m from the excavated surface of the soil plug; P2 is the soil pressure set at P1, P3 Corresponding to the standard value of soil plug internal pressure obtained by monitoring and calculation of the soil pressure sensor in the middle section between the soil pressure sensors.
[0081] The earth pressure monitoring system includes earth pressure sensors 8. The earth pressure sensors 8 are divided into three groups and are arranged adjacent to each other along the driving direction. Image 6 and Figure 7 As shown, the weighted average or the sequence of the real-time earth pressure values measured by all the earth pressure sensors 8 in each group are P1, P2 and P3, respectively. Each group of earth pressure sensors 8 are arranged at annular intervals along the circumference of the soil bin 1, and are in direct contact with the soil on the inner wall of the soil bin 1. The axial distance between a group of earth pressure sensors at the end and the earth plug excavation surface is within 1m, and a group of earth pressure sensors in the middle are arranged in the middle section of the front and rear earth pressure sensors.
[0082] The rear side of the stress applying device at the rear end of the soil bin 1 is also provided with an emergency door closing system 6. The emergency door closing system 6 includes a door panel structure and its control system, which maintain the same shape as the tunnel section to be built; during normal excavation, the door panel structure is open In case of sudden water or sand gushing in the ground, the unearthed device is withdrawn, and the door panel structure is closed in time through the control system. At this time, the face 9 is separated from the equipment and personnel in the power silo and the lining silo of the excavation device, which ensures the safety of the equipment and personnel in the excavation device. When the condition of the tunnel face 9 is stable, the door panel structure is retracted through the control system, and personnel and equipment are organized to reinforce or improve the tunnel face 9 and the surrounding rock in front.
[0083] If necessary, the stress application device and the emergency door closing system 6 can be combined into one. During excavation, if no stress is required, adjust the baffle plate to the open state through the oil cylinder, so that the soil body is not stressed; if there is a water inrush and mud rush, adjust the baffle plate to the closed state through the oil cylinder (the width of the baffle plate should meet the closing condition).
[0084] The above-mentioned embodiments are only to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. On the premise of not departing from the design spirit of the present invention, those of ordinary skill in the art can make various kinds of technical solutions of the present invention. Variations and improvements should fall within the protection scope determined by the claims of the present invention.
