TBM construction method in narrow space

Abstract

The present invention discloses a TBM construction method for a narrow space, including: step 1, excavating a starting hole at one end of the tunnel along the center line of the tunnel; step 2, using advanced geological survey to judge the state of the surrounding rock in a certain mileage, which is divided into hard rock conditions and soft rock conditions. If it is a hard rock condition, the mileage is divided from the starting point into a stress supplement section, a buffer section and a tunneling section, and the stress supplement section and the buffer section account for 1 / 100 to 3 / 100 and 1 / 20 to 3 / 20 of the length of the mileage respectively, and the remainder is the tunneling section, and the TBM is pushed into the starting hole to start construction; if it is a soft rock condition, the mileage is divided from the starting point into a cross-progressing stable section and an advancing stage; as the TBM advances forward, the installation of the pipe segment and the grouting of the pipe segment area are done at the same time; until the construction of the full mileage is completed. The present invention meets the needs of both soft soil layers and superhard rock layers.

Description

Technical Field

[0001] The present invention relates to the technical field of TBM construction, and more specifically, to a narrow space TBM construction method. Background Art

[0002] The TBM construction method refers to the construction method of tunnel construction using a full-section tunnel boring machine. TBM can realize continuous operation of construction processes such as excavation, support, and slag discharge. It has the advantages of fast construction speed, shortened construction period, small impact force, small damage to surrounding rocks, almost no loosening and falling blocks, small risk of collapse, light support workload, and small impact on surrounding residents and structures. Many construction projects are located in mountainous areas. In tunnel construction projects in mountainous areas, due to the large number of mountains, the construction space is relatively small, the surrounding rock layer is inhomogeneous, or even the surrounding rock layer state is very different, it is necessary to have a shield machine with two different functional modes of earth pressure (EPB) / TBM with a core screw type slag discharge. However, there is no way to complete the conversion between the EPB and TBM modes in a small space. The only way is to change the operation method in the TBM mode to realize tunnel construction with very different surrounding rock states. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0004] Another object of the present invention is to provide a TBM construction method in a narrow space, which can meet the needs of both soft soil layers and super hard rock layers by adjusting the excavation method and manually changing the excavation parameters without switching the TBM mode in a narrow operating space.

[0005] In order to achieve these purposes and other advantages according to the present invention, a narrow space TBM construction method is provided, comprising:

[0006] Step 1: Dig a starting hole along the center line of the tunnel at one end of the tunnel. The diameter of the starting hole is slightly larger than the selected TBM, and the hole wall can be tightened by the TBM support shoe;

[0007] Step 2: Use advanced geological survey to determine the surrounding rock conditions during the 45-65m mileage, which are divided into hard rock conditions and soft rock conditions.

[0008] If it is hard rock condition, the mileage is divided into stress supplement section, buffer section and excavation section according to the travel direction, and TBM parameters are manually adjusted for excavation. The stress supplement section and buffer section account for 1 / 100 to 3 / 100 and 1 / 20 to 3 / 20 of the mileage length respectively, and the remainder is the excavation section. The TBM is pushed into the starting tunnel and construction begins;

[0009] Wherein, the construction method of the stress supplementation section includes:

[0010] The first step is to use the TBM's own drilling rig to drill holes. The drilling range covers the arch part of 90-120°, the drilling angle is 8-10°, the drilling depth is 20-35m, the hole diameter is 100-110mm, and high-pressure water is injected into the hole to release stress.

[0011] The second step is to use the TBM cutterhead to advance along the center line of the tunnel using the short advance principle. The advance of each cycle is 0.5 to 1 m, and the average advance speed of the TBM is controlled at 5 to 8 mm / min. As the TBM advances forward, the segment installation and grouting of the segment area are completed at the same time.

[0012] Step 3: Repeat step 2 until the stress supplementation section is completed;

[0013] The construction method of the buffer section and the excavation section includes:

[0014] Directly use the TBM cutterhead to advance along the center line of the tunnel. The advance of each cycle in the buffer section is 1-2m, and the average advance speed of the TBM is controlled at 8-10mm / min. After every 3-5 cycles, high-pressure water is continuously injected into the borehole until the end of the borehole is no longer injected. The advance of each cycle in the excavation section is 2-2.5m, and the average advance speed of the TBM is controlled at 10-12mm / min. After every 3-5 cycles, high-pressure water is continuously injected into the borehole until the end of the borehole is no longer injected. As the TBM advances forward, the installation of the pipe segments and the grouting of the pipe segment area are completed at the same time until the construction of the entire mileage is completed.

[0015] If it is a soft rock condition, the mileage is divided into a cross-continuous stable section and an advancing stage from the starting point, and the TBM parameters are manually adjusted for excavation. The mileage length of the single stable section and the advancing stage is 4 to 6 meters. The construction method of the stable section and the advancing stage includes: using the TBM cutter head to excavate forward along the center line of the tunnel, the advancement of each cycle in the stable section is 0.5 to 1.5 meters, and the average excavation speed of the TBM is controlled at 5 to 8 mm / min; the advancement of each cycle in the advancing stage is 1.5 to 3 meters, and the average excavation speed of the TBM is controlled at 8 to 12 mm / min; as the TBM excavates forward, the installation of the pipe segment and the grouting of the pipe segment area are done at the same time; until the construction of the entire mileage is completed;

[0016] If it is a connecting section of hard rock conditions and soft rock conditions, the detection section mileage will be shortened at a descending rate of 5 to 10% until one type of rock condition accounts for more than 95% of the detection mileage. Within the 95% mileage range, it will be processed according to this rock condition, and within the 5% mileage range, excavation will be carried out according to the current TBM parameters and the automatic excavation mode will be started.

[0017] Preferably, in step 2, the TMB's own laser guidance system is used to track and control the tunnel centerline, and after each cycle, the deviation value of the excavation direction is no more than 2 mm.

[0018] Preferably, the pipe segment is close to the surrounding rock and is composed of 3 to 5 prefabricated blocks. The pipe segment can be assembled in a ring shape, and a plurality of anchor rods / grouting holes are reserved on the pipe segment.

[0019] Preferably, the starting hole in step 1 is a city gate hole type, and the walking part of the boot is an arc shape.

[0020] Preferably, in the supplementary stress section, the advancing speed of the TBM cutterhead is 30-45% of the maximum excavation speed value, in the buffer section, the advancing speed of the TBM cutterhead is 45-65% of the maximum excavation speed value, in the excavation section, the advancing speed of the TBM cutterhead is 65-80% of the maximum excavation speed value, and in the stable section and the advancing stage, the advancing speed of the TBM cutterhead is 15-30% of the maximum excavation speed value.

[0021] Preferably, in the supplementary stress section, the buffer section and the excavation section, the torque variation range of the TBM cutter head is no more than 10%.

[0022] Preferably, during the grouting operation, after the slurry fills the anchor rod / grouting hole and the slurry is reversed, the anchor rod body is quickly inserted and fixed at the anchor rod / grouting hole.

[0023] Preferably, the anchor rod / grouting hole is fixed by a wooden wedge.

[0024] The present invention has at least the following beneficial effects:

[0025] First, the TBM construction method for a narrow space provided by the present invention can complete the construction of a tunnel with a large difference in the state of the surrounding rock layer without switching the shield machine mode in the narrow space;

[0026] Secondly, the TBM construction method for narrow spaces provided by the present invention does not adjust the TBM operating parameters based on experience according to the state of the surrounding rock layer, but rather divides the construction section into different sections on purpose, manually controls the operating parameters in each section within a certain range, and then fine-tunes them according to the state of the surrounding rock layer, which can improve the overall construction efficiency and shorten the construction period;

[0027] Thirdly, the TBM construction method for a narrow space provided by the present invention divides the construction section into sections according to the state of the surrounding rock layer, and further grades the construction process within each section, which effectively reduces the wear of the TBM cutterhead and greatly reduces the replacement rate of the TBM cutterhead.

[0028] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with specific technical solutions so that those skilled in the art can implement the invention with reference to the description.

[0030] It should be understood that terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0031] The present invention provides a narrow space TBM construction method, comprising:

[0032] Step 1: Dig a starting hole along the center line of the tunnel at one end of the tunnel. The diameter of the starting hole is slightly larger than the selected TBM, and the hole wall can be tightened by the TBM support shoe;

[0033] Step 2: Use advanced geological survey to determine the surrounding rock conditions during the 45-65m mileage, which are divided into hard rock conditions and soft rock conditions.

[0034] If it is hard rock condition, the mileage is divided into stress supplement section, buffer section and excavation section according to the travel direction, and TBM parameters are manually adjusted for excavation. The stress supplement section and buffer section account for 1 / 100 to 3 / 100 and 1 / 20 to 3 / 20 of the mileage length respectively, and the remainder is the excavation section. The TBM is pushed into the starting tunnel and construction begins;

[0035] Wherein, the construction method of the stress supplementation section includes:

[0036] The first step is to use the TBM's own drilling rig to drill holes. The drilling range covers the arch part of 90-120°, the drilling angle is 8-10°, the drilling depth is 20-35m, the hole diameter is 100-110mm, and high-pressure water is injected into the hole to release stress.

[0037] The second step is to use the TBM cutterhead to advance along the center line of the tunnel using the short advance principle. The advance of each cycle is 0.5 to 1 m, and the average advance speed of the TBM is controlled at 5 to 8 mm / min. As the TBM advances forward, the segment installation and grouting of the segment area are completed at the same time.

[0038] Step 3: Repeat step 2 until the stress supplementation section is completed;

[0039] The construction method of the buffer section and the excavation section includes:

[0040] Directly use the TBM cutterhead to advance along the center line of the tunnel. The advance of each cycle in the buffer section is 1-2m, and the average advance speed of the TBM is controlled at 8-10mm / min. After every 3-5 cycles, high-pressure water is continuously injected into the borehole until the end of the borehole is no longer injected. The advance of each cycle in the excavation section is 2-2.5m, and the average advance speed of the TBM is controlled at 10-12mm / min. After every 3-5 cycles, high-pressure water is continuously injected into the borehole until the end of the borehole is no longer injected. As the TBM advances forward, the installation of the pipe segments and the grouting of the pipe segment area are completed at the same time until the construction of the entire mileage is completed.

[0041] If it is a soft rock condition, the mileage is divided into a cross-continuous stable section and an advancing stage from the starting point, and the TBM parameters are manually adjusted for excavation. The mileage length of the single stable section and the advancing stage is 4 to 6 meters. The construction method of the stable section and the advancing stage includes: using the TBM cutter head to excavate forward along the center line of the tunnel, the advancement of each cycle in the stable section is 0.5 to 1.5 meters, and the average excavation speed of the TBM is controlled at 5 to 8 mm / min; the advancement of each cycle in the advancing stage is 1.5 to 3 meters, and the average excavation speed of the TBM is controlled at 8 to 12 mm / min; as the TBM excavates forward, the installation of the pipe segment and the grouting of the pipe segment area are done at the same time; until the construction of the entire mileage is completed;

[0042] If it is a connecting section of hard rock conditions and soft rock conditions, the detection section mileage will be shortened at a descending rate of 5 to 10% until one type of rock condition accounts for more than 95% of the detection mileage. Within the 95% mileage range, it will be processed according to this rock condition, and within the 5% mileage range, excavation will be carried out according to the current TBM parameters and the automatic excavation mode will be started.

[0043] In the above technical scheme, TBM operation can be divided into manual control and automatic control. The construction section is purposefully divided into different sections. The operating parameters in each section are manually controlled within a certain range and then fine-tuned according to the state of the surrounding rock layer, which can improve the overall construction efficiency and shorten the construction period. Through advanced geological surveys in mountainous areas, the rock conditions of the front excavation section are determined. Under hard rock conditions, the pre-survey section is divided into the construction section stress supplement section, buffer section and excavation section to manually adjust the TBM parameters for excavation. First, the stress supplement section is drilled with the TBM's own drilling rig, and high-pressure water is injected into the hole to release stress. The subsequent buffer section and excavation section continue to inject high-pressure water into the hole to release stress every 3 to 5 cycles with the help of the drilling of the stress supplement section until the end of the borehole. Under soft rock conditions, the stability and excavation strength of the TBM excavation are guaranteed by alternating stable sections and advancing stages. The section-by-section treatment is carried out according to the state of the surrounding rock layer, and the graded treatment is carried out within the construction mileage of each section, which effectively reduces the wear of the TBM cutterhead and greatly reduces the replacement rate of the TBM cutterhead.

[0044] In one of the technical solutions, in step 2, TMB's built-in laser guidance system is used to track and control the tunnel centerline. After each cycle, the deviation value of the excavation direction is no more than 2mm. The guidance accuracy required in tunnels with narrow space is higher.

[0045] In one of the technical solutions, the pipe segment is tightly attached to the surrounding rock and is composed of 3 to 5 prefabricated blocks. The pipe segment can be assembled in a ring shape. A plurality of anchor rods / grouting holes are reserved on the pipe segment. Cement mortar is injected through the reserved anchor rods / grouting holes to fill the gap between the pipe segment and the excavated surrounding rock. Concrete is molded in the working area of ​​the TBM support shoe on the pipe segment to facilitate the subsequent normal operation of the TBM support shoe and protect the pipe segment from being crushed by the support shoe in a narrow space.

[0046] In one of the technical solutions, the starting tunnel described in step one is a city gate tunnel type, and the walking part of the support boot is arc-shaped, which is convenient for fast and convenient construction in a small space, improves construction efficiency, shortens construction period, and reduces construction costs.

[0047] In one of the technical solutions, in the supplementary stress section, the advancing speed of the TBM cutterhead is 30-45% of the maximum excavation speed; in the buffer section, the advancing speed of the TBM cutterhead is 45-65% of the maximum excavation speed; in the excavation section, the advancing speed of the TBM cutterhead is 65-80% of the maximum excavation speed; in the stable section and the advance stage, the advancing speed of the TBM cutterhead is 15-30% of the maximum excavation speed. The advancing speed of the TBM in different stages is different, which reduces the radial and lateral impact loads on the cutter and protects the service life of the TBM cutterhead. In actual construction, the TBM advancement speed is first set to a smaller value, using a low speed, and then slowly adjusted to the preset range.

[0048] In one of the technical solutions, the torque variation range of the TBM cutterhead in the supplementary stress section, buffer section and excavation section is no more than 10%, to prevent partial cutter overload, generate impact load, reduce tool life and cause deterioration of the main bearing stress.

[0049] In one of the technical solutions, during the grouting operation, after the slurry fills the anchor rod / grouting hole and the slurry is reversed, the anchor rod body is quickly inserted and fixed at the anchor rod / grouting hole to increase the stability and impermeability of the lining.

[0050] In one of the technical solutions, the anchor / grouting holes are fixed with wooden wedges to ensure the stability of the lining.

[0051] Example

[0052] A mountain tunnel with a 1.53-kilometer hard rock condition and a 0.67-kilometer soft rock condition was selected as the construction section for experimental research. There are many mountains in this section, and the construction space is relatively narrow. Step 1: excavate the starting tunnel along the center line of the tunnel at one end of the tunnel. The diameter of the starting tunnel is slightly larger than the selected TBM, and the tunnel wall can be tightened by the TBM support boots; select the TBM first according to the mountain conditions, so that the mountain conditions can meet the excavation of the starting tunnel;

[0053] Step 2: Use advanced geological survey to determine that the 50m mileage ahead is hard rock condition, and divide the mileage from the starting point into stress supplement section, buffer section and excavation section. The stress supplement section and buffer section occupy 1m and 4m of the mileage length respectively, and the rest is the excavation section. Push the TBM into the starting hole and start construction; wherein the construction method of the stress supplement section includes:

[0054] The first step is to use the TBM's own drilling rig to drill holes. The drilling range covers the arch part of 90-120°, the drilling angle is 10°, the drilling depth is 25m, the hole diameter is 110mm, and high-pressure water is injected into the hole to release stress.

[0055] The second step is to use the TBM cutterhead to advance along the center line of the tunnel using the short advance principle. Each cycle advances 1m, and the average TBM advance speed is controlled at 8mm / min. As the TBM advances forward, the segment installation and grouting of the segment area are completed at the same time.

[0056] Step 3: Repeat step 2 until the stress supplementation section is completed;

[0057] The construction method of the buffer section and the excavation section includes:

[0058] Directly use the TBM cutterhead to advance along the center line of the tunnel. The advance of each cycle in the buffer section is 1m, and the average advance speed of the TBM is controlled at 10mm / min; the advance of each cycle in the excavation section is 2m, and the average advance speed of the TBM is controlled at 12mm / min; after every 5 cycles, continue to inject high-pressure water into the borehole, and as the TBM advances forward, install the pipe segments and grout the pipe segment area at the same time until the full mileage construction is completed;

[0059] Continue geological survey and determine that the next 50m is hard rock. Repeat the above operation until the hard rock section is completed.

[0060] Continue geological exploration. If it is determined that the 50m mileage ahead is a connecting section of hard rock conditions and soft rock conditions, shorten the exploration mileage by 10%. If it is determined that the 45m mileage ahead is a connecting section of hard rock conditions and soft rock conditions, continue to shorten the exploration mileage by 10%. If it is determined that the 40m mileage ahead is a connecting section of hard rock conditions and soft rock conditions, continue to shorten the exploration mileage by 10%. If it is determined that the 35m mileage ahead is a connecting section of hard rock conditions and soft rock conditions, continue to shorten the exploration mileage by 10%. If it is determined that the 30m mileage ahead is a hard rock condition, repeat the above operation until the construction of the hard rock section is completed.

[0061] Continuing geological survey, it is determined that the 50m mileage ahead is soft rock conditions, and the mileage is divided from the starting point into a cross-progressive stable section and an advancing stage. The construction methods of the stable section and the advancing stage include: using the TBM cutter head to advance along the center line of the tunnel, with an advance of 0.5m per cycle in the stable section, and the average TBM advancement speed controlled at 5mm / min; the advance of 1.5m per cycle in the advancing section, and the average TBM advancement speed controlled at 8mm / min; as the TBM advances forward, the installation of the pipe segments and the grouting of the pipe segment area are carried out at the same time; until the construction of the entire mileage is completed, under the narrow mountain tunnel construction conditions, the entire construction process does not require the replacement of the EPB and TBM modes, and the construction is successfully completed.

[0062] The number of equipment and processing scale described here are used to simplify the description of the present invention. The application, modification and variation of the narrow space TBM construction method of the present invention will be obvious to those skilled in the art.

[0063] As described above, according to the present invention, the present invention at least includes the following beneficial effects:

[0064] First, the TBM construction method for a narrow space provided by the present invention can complete the construction of a tunnel with a large difference in the state of the surrounding rock layer without switching the shield machine mode in the narrow space;

[0065] Secondly, the TBM construction method for narrow spaces provided by the present invention does not adjust the TBM operating parameters based on experience according to the state of the surrounding rock layer, but rather divides the construction section into different sections on purpose, and the operating parameters in each section are fine-tuned within a certain range according to the state of the surrounding rock layer, which can improve the overall construction efficiency and shorten the construction period;

[0066] Thirdly, the TBM construction method for a narrow space provided by the present invention divides the construction section into sections according to the state of the surrounding rock layer, and further grades the construction process within the mileage of each section, which greatly reduces the replacement rate of the TBM cutterhead.

[0067] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the technical solutions shown and described herein.

Claims

1. A narrow space TBM construction method, characterized in that: include: Step 1: Dig a starting hole along the center line of the tunnel at one end of the tunnel. The diameter of the starting hole is slightly larger than the selected TBM, and the hole wall can be tightened by the TBM support shoe; Step 2: Use advanced geological survey to determine the surrounding rock conditions during the 45-65m mileage, which are divided into hard rock conditions and soft rock conditions. If it is hard rock condition, the mileage is divided into stress supplement section, buffer section and excavation section according to the travel direction, and TBM parameters are manually adjusted for excavation. The stress supplement section and buffer section account for 1 / 100 to 3 / 100 and 1 / 20 to 3 / 20 of the mileage length respectively, and the remainder is the excavation section. The TBM is pushed into the starting tunnel and construction begins; Wherein, the construction method of the stress supplementation section includes: The first step is to use the TBM's own drilling rig to drill holes. The drilling range covers the arch part of 90-120°, the drilling angle is 8-10°, the drilling depth is 20-35m, the hole diameter is 100-110mm, and high-pressure water is injected into the hole to release stress. The second step is to use the TBM cutterhead to advance along the center line of the tunnel using the short advance principle. The advance of each cycle is 0.5 to 1 m, and the average advance speed of the TBM is controlled at 5 to 8 mm / min. As the TBM advances forward, the segment installation and grouting of the segment area are completed at the same time. Step 3: Repeat step 2 until the stress supplementation section is completed; The construction method of the buffer section and the excavation section includes: Directly use the TBM cutterhead to advance along the center line of the tunnel. The advance of each cycle in the buffer section is 1-2m, and the average advance speed of the TBM is controlled at 8-10mm / min. After every 3-5 cycles, high-pressure water is continuously injected into the borehole until the end of the borehole is no longer injected. The advance of each cycle in the excavation section is 2-2.5m, and the average advance speed of the TBM is controlled at 10-12mm / min. After every 3-5 cycles, high-pressure water is continuously injected into the borehole until the end of the borehole is no longer injected. As the TBM advances forward, the installation of the pipe segments and the grouting of the pipe segment area are completed at the same time until the construction of the entire mileage is completed. If the conditions are soft rock, the mileage is divided into a cross-processed stable section and an advancing stage from the starting point, and the TBM parameters are manually adjusted for excavation. The mileage length of a single stable section and an advancing stage is 4 to 6 meters. The construction methods of the stable section and the advancing stage include: using the TBM cutterhead to excavate forward along the center line of the tunnel, with an advance of 0.5 to 1.5 meters per cycle in the stable section, and the average excavation speed of the TBM controlled at 5 to 8 mm / min; the advance of each cycle in the advancing stage is 1.5 to 3 meters, and the average excavation speed of the TBM is controlled at 8 to 12 mm / min; as the TBM excavates forward, the installation of the pipe segment and the grouting of the pipe segment area are done at the same time; until the construction of the entire mileage is completed; If it is a connecting section of hard rock conditions and soft rock conditions, the detection section mileage will be shortened at a descending rate of 5 to 10% until one type of rock condition accounts for more than 95% of the detection mileage. Within the 95% mileage range, it will be processed according to this rock condition, and within the 5% mileage range, excavation will be carried out according to the current TBM parameters and the automatic excavation mode will be started.

2. The narrow space TBM construction method according to claim 1, characterized in that: In step 2, TMB’s built-in laser guidance system is used to track and control the tunnel centerline. After each cycle, the deviation in the excavation direction is no more than 2 mm.

3. The narrow space TBM construction method according to claim 2, characterized in that: The pipe segment is close to the surrounding rock and is composed of 3 to 5 prefabricated blocks. The pipe segment can be assembled in a ring shape, and a plurality of anchor rods / grouting holes are reserved on the pipe segment.

4. The narrow space TBM construction method according to claim 3, characterized in that: The starting tunnel described in step 1 is a city gate tunnel type, and the walking part of the boots is an arc shape.

5. The narrow space TBM construction method according to claim 4, characterized in that: In the supplementary stress section, the advancing speed of the TBM cutterhead is 30-45% of the maximum excavation speed; in the buffer section, the advancing speed of the TBM cutterhead is 45-65% of the maximum excavation speed; in the excavation section, the advancing speed of the TBM cutterhead is 65-80% of the maximum excavation speed; in the stable section and advance stage, the advancing speed of the TBM cutterhead is 15-30% of the maximum excavation speed.

6. The narrow space TBM construction method according to claim 5, characterized in that: In the supplementary stress section, buffer section and excavation section, the torque variation range of the TBM cutterhead is no more than 10%.

7. The narrow space TBM construction method according to claim 6, characterized in that: During the grouting operation, after the slurry fills the anchor rod / grouting hole and the slurry is reversed, the anchor rod body is quickly inserted and fixed at the anchor rod / grouting hole.

8. The narrow space TBM construction method according to claim 7, characterized in that: The anchor / grouting holes are fixed with wooden wedges.