Method for excavating connecting channel by using carbon dioxide laser device

Abstract

The invention discloses a method for excavating a contact channel by using a carbon dioxide laser device, which comprises the following steps: S1, freezing construction is carried out in a target stratum until frozen walls intersect and soil bodies in an excavation pierced path of the contact channel are all frozen; an excavation contour line of the connection channel is drawn on the tunnel face according to the excavation rough diameter, the excavation contour line is located in the enclosure of the frozen wall, and a closed ring A is defined by the excavation contour line; s2, a cutting line is drawn on the tunnel face; the cutting line is located in the closed ring A defined by the excavation contour line; s3, using a carbon dioxide laser device to construct a cutting groove in the surface of the frozen soil body at the tunnel face along the cutting line; and S4, performing manual crushing on the frozen soil body between the cutting grooves. The method can obviously shorten the excavation period, improve the construction precision and safety, and is suitable for a contact channel project constructed by a freezing method.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel excavation. Specifically, it is a method for excavating a connecting passage using a carbon dioxide laser device. Background Art

[0002] With the continuous acceleration of the urbanization process in China, the urban traffic pressure is increasing day by day. To relieve the traffic pressure, the pace of subway construction across the country has significantly accelerated. According to the requirements of the "Code for Design of Subways" in China, when the continuous length of the subway tunnel exceeds 600m, a connecting passage needs to be set up to ensure the safety and emergency evacuation requirements during subway operation. Therefore, the number of construction projects for connecting passages has increased accordingly.

[0003] At present, most of the construction of connecting passages adopts the traditional construction method of "freezing method for water stop + manual pneumatic pick excavation". Although this method has certain applicability in practice, it also has significant disadvantages. To ensure construction safety, the thickness of the frozen wall is usually designed to be relatively large, which increases the difficulty of thawing the frozen soil during excavation, resulting in low construction efficiency and a long excavation period. In addition, manual pneumatic pick excavation may also cause uncontrollable disturbances to the frozen soil wall, further affecting the construction quality and progress. Moreover, during the excavation construction, external disturbances will change the stress distribution of the frozen wall, and in severe cases, it may cause the frozen soil to collapse uncontrollably, posing a danger.

[0004] To solve the above problems, there is an urgent need in this field for an advanced technology that can improve the excavation efficiency of connecting passages, shorten the construction period, and reduce the disturbance to the frozen wall. Summary of the Invention

[0005] For this reason, the technical problem to be solved by the present invention is to provide a method for excavating a connecting passage using a carbon dioxide laser device. By using the carbon dioxide laser device to cut the frozen soil within the excavation contour and separating the frozen soil within the excavation contour into uniform blocks, supplemented by manual crushing, it can significantly shorten the excavation period, improve the construction accuracy and safety, and is applicable to the connecting passage project constructed by the freezing method.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] A method for excavating a connecting passage using a carbon dioxide laser device, comprising the following steps:

[0008] S1. Conduct freezing construction in the target formation until the frozen wall is formed in a circle and the soil within the excavation diameter of the connecting passage has been frozen; draw the excavation contour line of the connecting passage on the heading face according to the excavation diameter, the excavation contour line is located within the frozen wall, and the excavation contour line encloses a closed circle A;

[0009] S2. Draw a cutting line on the tunnel face; the cutting line is located within the closed circle A surrounded by the excavation contour line;

[0010] S3, using a carbon dioxide laser device to construct a cutting groove on the frozen soil surface of the tunnel face along the cutting line;

[0011] S4, artificially crushing the frozen soil body between the cutting grooves;

[0012] S5. Repeat steps S2 to S4 until the communication channel is connected.

[0013] In the above-mentioned method of excavating a communication channel using a carbon dioxide laser device, in step S2, the cutting line includes a circumferential cutting line, a transverse cutting line and a longitudinal cutting line; wherein, on the tunnel face, the circumferential cutting line is parallel to the excavation contour line and forms a closed circle B, and the transverse cutting line and the longitudinal cutting line are both located within the closed circle B formed by the circumferential cutting line.

[0014] In the above method of excavating a communication channel using a carbon dioxide laser device, in step S2, the transverse cutting line intersects the longitudinal cutting line, and both ends of the transverse cutting line and both ends of the longitudinal cutting line are connected to the circumferential cutting line.

[0015] In the above-mentioned method of excavating a communication channel using a carbon dioxide laser device, in step S2, the number of the transverse cutting lines and the longitudinal cutting lines is at least 2; all the transverse cutting lines are parallel to the horizontal center line of the tunnel face, and the transverse cutting lines are arranged at equal intervals in the vertical direction within the closed circle B surrounded by the circumferential cutting lines; all the longitudinal cutting lines are parallel to the vertical center line of the tunnel face, and the longitudinal cutting lines are arranged at equal intervals in the horizontal direction within the closed circle B surrounded by the circumferential cutting lines.

[0016] In the above method of excavating a communication channel using a carbon dioxide laser device, in step S2, the number of the circumferential cutting lines is 1, and the spacing between the circumferential cutting lines and the excavation contour line is 500-600 mm; the distance between two adjacent transverse cutting lines is 1000-2000 mm, and the distance between two adjacent longitudinal cutting lines is 500-1000 mm; the transverse cutting lines and the longitudinal cutting lines are arranged equidistantly, so that the isolated frozen soil column is evenly divided into multiple regular small areas, and the heat generated by the laser can be evenly conducted to the frozen soil blocks around the cutting groove, thereby effectively maintaining the overall stability of the frozen soil column. Small pieces of frozen soil of appropriate size can be fully softened under the action of reasonable laser power, but will not collapse, thereby greatly improving the efficiency of subsequent artificial crushing.

[0017] For the above method of excavating the connecting passage by using a carbon dioxide laser device, in step S3, first construct a cutting groove along the circumferential cutting line, and then construct a cutting groove along the transverse cutting line or the longitudinal cutting line.

[0018] First, construct a cutting groove along the circumferential cutting line to obtain a circumferential cutting groove. An isolated frozen soil column is formed inside the circumferential cutting groove, which is separated from the surrounding frozen soil. At this time, the radial stress acting on the isolated frozen soil column is relieved, and the channel for heat transfer from the frozen wall to the isolated frozen soil column in the radial direction is cut off. The strength of the isolated frozen soil column will decrease accordingly, which is beneficial to the subsequent transverse and longitudinal cutting.

[0019] Preferably, after constructing the cutting groove along the circumferential cutting line, first construct the transverse cutting groove, and then construct the longitudinal cutting groove; when constructing the transverse cutting groove or the longitudinal cutting groove, construct it in the order from bottom to top.

[0020] Preferably, when performing manual crushing, also construct it in the order from bottom to top, first crush the frozen soil near the bottom of the excavation contour line, and then crush the frozen soil near the top of the excavation contour line.

[0021] There is self-weight stress inside the frozen soil. When constructing the transverse cutting groove in the order from bottom to top, the self-weight stress of the isolated frozen soil column inside the circumferential cutting groove changes. The frozen soil above the transverse cutting groove is prone to crack under the action of self-weight stress, and the frozen soil body becomes loose. However, since the circumferential cutting groove has separated the isolated frozen soil column from the frozen wall, these cracks generated by self-weight stress will not damage the frozen wall. If the longitudinal cutting groove is constructed first, the isolated frozen soil column will be divided into smaller frozen soil blocks. When constructing the transverse cutting groove later, the self-weight stress of each frozen soil block is relatively small, and the effect of self-weight stress cannot be fully utilized.

[0022] The construction sequence of the longitudinal cutting groove from bottom to top and the manual crushing sequence match the construction sequence of the transverse cutting groove, so that the time consumed from the completion of the transverse cutting groove processing of each frozen soil block to the construction of the longitudinal cutting groove and manual crushing is basically the same, thereby ensuring that the thawing states of each frozen soil block are balanced and consistent, and reducing the construction risks caused by uneven local thawing.

[0023] In the above method for excavating a connecting passage by using a carbon dioxide laser device, in step S3, when constructing the cutting groove along the circumferential cutting line, the power of the laser used is greater than the power of the laser used when constructing the cutting groove along the transverse cutting line or the longitudinal cutting line. When constructing the circumferential cutting groove, the clamping force on the frozen soil body at the excavation face is large, and it is easy to cut the groove when the laser power is large; when constructing the transverse (longitudinal) cutting groove, the frozen soil body on the excavation face has been separated from the frozen soil body of the frozen wall in the radial direction, and the construction is relatively easy. In order to save costs, a laser with a smaller power can be used. In actual construction, the specific laser power used should be adjusted according to the spacing between the cutting lines (that is, the volume of the frozen soil blocks between the cutting grooves).

[0024] In the above method for excavating a connecting passage by using a carbon dioxide laser device, in step S3, the depth of the cutting groove is 200 - 400 mm; when constructing the cutting groove along the circumferential cutting line, the laser power used is 11 - 14 kW; when constructing the cutting groove along the transverse cutting line or the longitudinal cutting line, the power of the laser used is 8 - 10 kW.

[0025] If the cutting groove is too shallow, the cyclic footage is small, resulting in high costs and a long construction period; if the cutting groove is too deep, the efficiency of discharging the broken frozen soil in the cutting groove is reduced, and the broken soil at the bottom of the cutting groove slowly accumulates and absorbs part of the laser energy, so that the laser energy is not completely used to cut the frozen soil at the bottom of the groove.

[0026] The depths of the circumferential cutting groove, the transverse cutting groove, and the longitudinal cutting groove should preferably be kept equal. If the depth of the circumferential cutting groove is greater than the depths of the transverse cutting groove and the longitudinal cutting groove, a large - scale step will be generated between the bottom of the circumferential cutting groove and the bottom of the transverse cutting groove, which will lead to an increase in the need to use manual pneumatic picks to break the frozen soil, and more time and physical strength will be consumed during construction. Similarly, when the depth of the circumferential cutting groove is less than the depths of the transverse cutting groove and the longitudinal cutting groove, it will also lead to an increase in the time and physical strength consumed during manual breaking of the frozen soil. In addition, it will also cause waste of laser energy during the construction of the transverse cutting groove and the longitudinal cutting groove.

[0027] In the above method for excavating a connecting passage by using a carbon dioxide laser device, in step S3, the following steps are further included: after constructing the cutting groove along the circumferential cutting line, first perform frozen soil disturbance construction, and then construct the cutting groove along the transverse cutting line or the longitudinal cutting line; when performing frozen soil disturbance construction, use the carbon dioxide laser device to irradiate the surface of the frozen soil located within the closed circle B surrounded by the circumferential cutting line; the laser power used during frozen soil disturbance construction is 4 - 6 kW.

[0028] First, perform frozen soil disturbance construction with a laser at a relatively low power (4 - 6 kW), causing the frozen soil mass at the isolated frozen soil column to become loose. Further, when constructing the transverse cutting groove and the longitudinal cutting groove, a laser with a relatively low power can be used to complete the operation. When the laser power used is relatively low, the thermal disturbance to the isolated frozen soil column during the cutting process is reduced, thereby preventing the sudden collapse of the frozen soil mass between the cutting grooves and causing danger. In addition, the laser with a relatively low power can reduce energy consumption and at the same time reduce the thermal load during the operation of the equipment, preventing the laser equipment from malfunctioning due to overheat protection.

[0029] For the method of excavating a connection passage using a carbon dioxide laser device described above, after each completion of step S4, the following steps are immediately carried out: Remove the frozen soil mass within the excavation contour line and perform support construction on the exposed passage wall of the connection passage.

[0030] The technical solution of the present invention has achieved the following beneficial technical effects:

[0031] 1. The present invention provides a method for excavating a connection passage using a carbon dioxide laser device. By reasonably planning the layout of the cutting lines on the excavation face, it is ensured that after cutting with a carbon dioxide laser along the cutting lines, cutting grooves with reasonable distribution and depth are formed. By reasonably planning the spacing between the cutting lines, the size of the frozen soil blocks between the cutting grooves is appropriate. After constructing the cutting grooves with a laser power of a specific power, the frozen soil blocks between the cutting grooves are softened compared to before the cutting groove construction, but will not collapse randomly. This is beneficial to improving the efficiency of manual pneumatic pick breaking. At the same time, the reasonable layout of the cutting lines ensures that when cutting the frozen soil with a carbon dioxide laser to construct the cutting grooves, the frozen soil at the excavation contour line is not affected by the heat generated during the carbon dioxide laser cutting and does not melt, ensuring the safety of the construction. On this basis, construct the cutting grooves along the cutting lines in the order of circumferential first, then transverse, and then longitudinal. The cutting grooves release the internal stress of the frozen soil in a reasonable order, reducing the construction difficulty during manual pneumatic pick breaking. It is also beneficial to isolate the heat generated during the construction of the transverse or longitudinal cutting grooves with the previously constructed circumferential cutting grooves, preventing the freezing wall from melting, and improving the efficiency and safety of excavating the connection passage in the frozen stratum. The method provided in the present invention effectively shortens the construction period, reduces the construction energy consumption and equipment load, significantly improves the construction economy, and enables the present invention to have obvious technical advantages and important promotion value in engineering practice.

[0032] 2. In the method provided by the present invention, the stress of the frozen soil column is released by first constructing the circumferential cutting groove. By keeping a distance of 500 - 600 mm between the circumferential cutting line and the excavation contour line, the heat insulation effect of the circumferential cutting groove is fully utilized to isolate the heat transfer between the frozen wall and the frozen soil column to be excavated, so that the frozen soil column to be excavated is quickly softened. At the same time, it prevents the frozen wall from thawing due to heat during the subsequent construction of the transverse and longitudinal cutting grooves, ensuring the overall construction safety. On this basis, the transverse cutting groove is constructed first, and then the longitudinal cutting groove is constructed. When constructing the transverse or longitudinal cutting groove, the construction sequence from bottom to top is adopted. The construction sequence of "transverse first and then longitudinal, from bottom to top" helps to make full use of the self-weight stress of the isolated frozen soil column, causing cracks in the isolated frozen soil column due to the change of self-weight stress and loosening the frozen soil mass. Further, when performing manual crushing, the operation is also carried out in the order from bottom to top, so that the time consumed by each frozen soil block from the completion of the cutting groove processing to the actual crushing is basically the same, ensuring the balanced thawing state of each frozen soil block. Combining the above technical measures can significantly improve the efficiency of frozen soil softening and crushing, reduce the construction risks caused by uneven local thawing, and thus overall improve the engineering construction efficiency and safety.

[0033] 3. In the method provided by the present invention, by dynamically adjusting the laser power in combination with the construction of frozen soil disturbance, the cutting difficulty is further reduced, the thermal disturbance and the thermal load of equipment operation are reduced. It not only prolongs the service life of the equipment, but also reduces the energy consumption, enables seamless connection between laser cutting and manual crushing, and effectively shortens the overall construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the positional relationship among the frozen wall, the excavation contour line and the circumferential cutting line at the excavation face of the connection passage in Embodiment 1 of the present invention;

[0035] Figure 2 Schematic diagram of the positional relationship among the circumferential cutting line, the transverse cutting line and the longitudinal cutting line at the excavation face of the connection passage in Embodiment 1 of the present invention;

[0036] Figure 3 Schematic diagram of the positional relationship among the constructed connection passage, the sump and the permanent support structure in Embodiment 1 of the present invention.

[0037] The reference numerals in the drawings are represented as: 1 - frozen wall; 2 - excavation contour line; 3 - cutting line; 301 - circumferential cutting line; 302 - transverse cutting line; 303 - longitudinal cutting line; 4 - permanent support structure; 5 - connection passage; 6 - sump. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] Embodiment 1

[0039] In this embodiment, a method for excavating a connecting passage by using a carbon dioxide laser device is provided. The specific steps of this method are as follows:

[0040] 1. Carry out freezing construction on the soil body of the proposed connecting passage in the target stratum. During freezing construction, freezing pipes are arranged on the periphery of the excavation diameter of the connecting passage 5, and low-temperature brine is circulated in the freezing pipes. Under the action of the low-temperature brine, the soil between adjacent freezing pipes gradually freezes, and finally a frozen wall 1 (i.e., the frozen wall 1 forms a circle) is formed. The frozen wall 1 surrounds the outside of the excavation diameter of the connecting passage 5, and the freezing pipes continuously transfer cold to the soil inside the excavation diameter of the connecting passage 5, so that the soil within the excavation diameter of the connecting passage 5 also freezes.

[0041] After the frozen wall 1 forms a circle and the soil inside the excavation diameter of the connecting passage 5 has been frozen, draw the excavation contour line 2 of the connecting passage 5 on the heading face. The excavation contour line 2 is drawn according to the excavation diameter of the connecting passage 5. The excavation contour line 2 encloses a closed circle A, and the excavation contour line 2 is located within the frozen wall 1. When excavating the connecting passage, after the soil within the closed circle A enclosed by the excavation contour line 2 is excavated, the exposed un-retained channel wall of the connecting passage is still frozen soil and is not prone to collapse.

[0042] 2. Draw a cutting line on the heading face

[0043] Draw a cutting line on the frozen soil surface within the closed circle A enclosed by the excavation contour line 2 on the heading face. As Figure 1 shown is the heading face during the excavation of the connecting passage 5. The figure shows the frozen wall 1, the excavation contour line 2 of the connecting passage 5, and the cutting line 3 (circumferential cutting line 301). The cross-shaped shadow in the figure represents the frozen soil within the frozen wall 1.

[0044] As Figure 2 shown is the excavation contour line 2 and the cutting line 3 inside the closed circle A enclosed by the excavation contour line 2. The cutting line 3 includes a circumferential cutting line 301, a transverse cutting line 302, and a longitudinal cutting line 303; among them, the circumferential cutting line 301 is parallel to the excavation contour line 2 and encloses a closed circle B; the transverse cutting line 302 and the longitudinal cutting line 303 are both located within the closed circle B enclosed by the circumferential cutting line 301.

[0045] On the heading face, the transverse cutting lines 302 extend in a horizontal direction parallel to the horizontal center line of the heading face, and the longitudinal cutting lines 303 extend in a vertical direction parallel to the vertical center line of the heading face. The transverse cutting lines 302 intersect with the longitudinal cutting lines 303. There are 3 transverse cutting lines and 3 longitudinal cutting lines. The transverse cutting lines are arranged at equal vertical intervals within the closed loop B formed by the circumferential cutting line, and the longitudinal cutting lines are arranged at equal horizontal intervals within the closed loop B formed by the circumferential cutting line. Both ends of the transverse cutting line 302 and both ends of the longitudinal cutting line 303 are connected to the circumferential cutting line 301. Specifically, both ends of the transverse cutting line are connected to the two side positions of the circumferential cutting line, and both ends of the longitudinal cutting line are respectively connected to the top and bottom of the circumferential cutting line.

[0046] In this embodiment, on the heading face, the distance between the circumferential cutting line 301 and the excavation contour line 2 is 500 mm. The frozen soil body between the excavation contour line 2 and the circumferential cutting line 301 plays a heat insulation role, reducing the transfer of heat generated during the construction of the cutting groove along the circumferential cutting line using a carbon dioxide laser to the frozen soil outside the excavation contour line 2. Furthermore, when the frozen soil body is subsequently broken by a manual pickaxe, the frozen soil body at the unlined excavation face of the already excavated connection tunnel remains stable, ensuring the safety of the construction.

[0047] In some other embodiments, the distance between the circumferential cutting line 301 and the excavation contour line 2 can also be other values within the range of 500 - 600 mm.

[0048] 3. Cutting frozen soil using a carbon dioxide laser device

[0049] First, cut the frozen soil along the circumferential cutting line 301. During construction, use a carbon dioxide laser device to irradiate the circumferential cutting line 301. At this time, the frozen soil body at the circumferential cutting line 301 melts and is removed, and a circumferential cutting groove is formed on the surface of the frozen soil body. In this embodiment, the depth of the circumferential cutting groove is 250 mm, and the laser power used during construction is 12 kW. After constructing the circumferential cutting groove on the excavation heading face, the frozen soil body within the closed loop B formed by the circumferential cutting groove is separated from the surrounding frozen soil, forming an isolated frozen soil column. At this time, the radial stress acting on the isolated frozen soil column is relieved, and the channel for transferring cold from the freezing wall to the isolated frozen soil column in the radial direction is cut off, and the strength of the isolated frozen soil column will decrease accordingly.

[0050] After the construction of the circumferential cutting groove is completed, first construct the transverse cutting groove along the transverse cutting line 302, and then construct the longitudinal cutting groove along the longitudinal cutting line 303. The depths of both the transverse cutting groove and the longitudinal cutting groove are 250 mm, and the laser power used during construction is 10 kW for both. In some other embodiments, the construction sequence of the transverse cutting groove and the longitudinal cutting groove can also be reversed.

[0051] In this embodiment, when constructing the circumferential cutting groove, the laser power used is greater than the laser power used in the construction of the transverse cutting groove and the longitudinal cutting groove. This is because when constructing the circumferential cutting groove, the clamping force on the frozen soil body at the excavation face is large, and grooving is easier when the laser power is large; when constructing the transverse (longitudinal) cutting groove, the frozen soil body on the excavation face has been separated from the frozen soil body of the frozen wall in the radial direction, and the construction is relatively easy. In order to save costs, a lower power laser can be used.

[0052] In this embodiment, the depth of the circumferential cutting groove, the transverse cutting groove and the longitudinal cutting groove are all 250 mm. In some other embodiments, the depth of the cutting groove can also be other values within the range of 200 to 400 mm. If the cutting groove is too shallow, the cycle footage is small, resulting in an extended construction period and high construction costs; if the cutting groove is too deep, the efficiency of discharging the broken frozen soil in the cutting groove is reduced, and the broken soil at the bottom of the cutting groove slowly gathers and absorbs part of the light energy, so that the energy is not completely used to remove the frozen soil at the bottom of the groove. In addition, the depths of the circumferential cutting groove, the transverse cutting groove and the longitudinal cutting groove should be kept equal. If the depth of the circumferential cutting groove is greater than the depth of the transverse cutting groove and the longitudinal cutting groove, a large range of steps will be generated between the bottom of the circumferential cutting groove and the bottom of the transverse (longitudinal) cutting groove, which will result in an increase in the need to use manual pneumatic picks to break the frozen soil, and the time and physical strength consumed during construction will be more. Similarly, the depth of the circumferential cutting groove is less than the depth of the transverse cutting groove and the longitudinal cutting groove, which will also increase the time and physical strength consumed when the frozen soil is frozen.

[0053] 4. Use artificial pneumatic picks to break up frozen soil

[0054] Use a pneumatic pick to manually break the frozen soil between the cutting grooves (i.e., the isolated frozen soil column within the closed circle B formed by the circumferential cutting grooves). When breaking, insert the pneumatic pick into the cutting groove to break the frozen soil between the cutting grooves. After the breaking is completed, the tunnel face returns to a basically flat state, and the cutting line can be continued.

[0055] 5. Provide support

[0056] After the frozen soil between the cutting grooves is broken, the remaining frozen soil within the excavation contour line 2 is further removed, and then the excavated communication channel 5 is supported. The support at this time is temporary support. After the communication channel is connected, permanent support is required to obtain a permanent support structure 4, which is a reinforced concrete structure. After the permanent support construction is completed, the freezing is stopped to allow the frozen wall to thaw naturally. Figure 3 It is a schematic diagram of the communication channel 5, the water collection well 6 and the permanent support structure 4 after the construction is completed.

[0057] Example 2

[0058] In this embodiment, a method for excavating a connecting passage by using a carbon dioxide laser device is provided. The difference between this method and the method in Embodiment 1 is that after the circumferential cutting groove construction is completed, the frozen soil disturbance construction is carried out first, and then the transverse cutting groove and the longitudinal cutting groove are constructed in sequence.

[0059] When carrying out the frozen soil disturbance construction, the surface of the isolated frozen soil column located within the closed circle B surrounded by the circumferential cutting line 301 is irradiated by using the carbon dioxide laser device. During the irradiation, a scanning-like method is adopted to make the laser emitted by the laser device "scan" the frozen soil surface row by row from bottom to top, so as to soften the frozen soil. The laser irradiation time at each position is controlled within 3 - 5 s, and the specific time is appropriately adjusted according to the temperature and density of the frozen soil. The function of the frozen soil disturbance construction is to increase the temperature of the isolated frozen soil column (but still below the freezing point), thereby reducing the strength and brittleness of the frozen soil, and reducing the workload and construction difficulty of manual crushing. After the frozen soil disturbance construction, the strength of the frozen soil column can be reduced by about 20%, which is convenient for the subsequent construction of the transverse cutting groove and the longitudinal cutting groove.

[0060] In this embodiment, the laser power during the construction of the circumferential cutting groove is 12 kW. When carrying out the frozen soil disturbance construction, the power of the laser used is 6 kW. When constructing the transverse cutting groove and the longitudinal cutting groove, the laser power used is 8 kW. That is to say, compared with not carrying out the frozen soil disturbance construction, carrying out the frozen soil disturbance construction first and then constructing the transverse cutting groove and the longitudinal cutting groove enables the use of a lower power laser to complete the construction when constructing the transverse cutting groove and the longitudinal cutting groove. When the laser power used is lower, the thermal disturbance to the frozen soil body between the cutting grooves during the cutting process is reduced, thereby preventing the sudden collapse of the frozen soil body between the cutting grooves and causing danger. In addition, the lower power laser can reduce energy consumption and at the same time reduce the thermal load during the operation of the equipment, preventing the laser equipment from being unable to operate normally due to overheat protection and delaying the construction progress.

[0061] Obviously, the above embodiments are only examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the claims of this patent application.

Claims

1. A method for excavating a connecting passage by using a carbon dioxide laser device, characterized in that The following steps are involved: S1. Freezing construction is performed in the target stratum until the freezing wall (1) is closed and the soil inside the excavation path of the communication channel (5) is frozen; an excavation contour line (2) of the communication channel (5) is drawn on the tunnel face according to the excavation path, the excavation contour line (2) is located within the encirclement of the freezing wall (1), and the excavation contour line (2) forms a closed circle A; S2, drawing a cutting line (3) on the tunnel face; the cutting line (3) is located within the closed circle A formed by the excavation contour line (2); S3, using a carbon dioxide laser device to construct a cutting groove on the frozen soil surface of the tunnel face along the cutting line (3); S4, artificially crushing the frozen soil body between the cutting grooves; S5. Repeat steps S2 to S4 until the communication channel (5) is connected.

2. The method for excavating a connecting passage by using a carbon dioxide laser device according to claim 1, characterized in that In step S2, the cutting line (3) includes a circumferential cutting line (301), a transverse cutting line (302) and a longitudinal cutting line (303); wherein, on the tunnel face, the circumferential cutting line (301) is parallel to the excavation contour line (2) and forms a closed circle B, and the transverse cutting line (302) and the longitudinal cutting line (303) are both located within the closed circle B formed by the circumferential cutting line (301).

3. The method for excavating a connecting passage by using a carbon dioxide laser device according to claim 2, characterized in that In step S2, the transverse cutting line (302) intersects with the longitudinal cutting line (303), and both ends of the transverse cutting line (302) and both ends of the longitudinal cutting line (303) are connected to the circumferential cutting line (301).

4. The method for excavating a connecting passage by using a carbon dioxide laser device according to claim 3, characterized in that In step S2, the number of the transverse cutting lines (302) and the longitudinal cutting lines (303) is at least 2; all the transverse cutting lines (302) are parallel to the horizontal center line of the tunnel face, and the transverse cutting lines (302) are arranged at equal intervals in the vertical direction within the closed circle B surrounded by the circumferential cutting lines (301); all the longitudinal cutting lines (303) are parallel to the vertical center line of the tunnel face, and the longitudinal cutting lines (303) are arranged at equal intervals in the horizontal direction within the closed circle B surrounded by the circumferential cutting lines (301).

5. The method for excavating a connecting passage by using a carbon dioxide laser device according to claim 4, characterized in that, In step S2, the number of the circumferential cutting lines (301) is one, and the spacing between the circumferential cutting line (301) and the excavation contour line (2) is 500 to 600 mm; the distance between two adjacent transverse cutting lines (302) is 1000 to 2000 mm, and the distance between two adjacent longitudinal cutting lines (303) is 500 to 1000 mm.

6. The method for excavating a connecting passage by using a carbon dioxide laser device according to claim 2, wherein In step S3, the cutting groove is first constructed along the circumferential cutting line (301), and then the cutting groove is constructed along the transverse cutting line (302) or the longitudinal cutting line (303).

7. The method for excavating a connection tunnel by using a carbon dioxide laser device according to claim 6, characterized in that, In step S3, when constructing the cutting groove along the circumferential cutting line (301), the power of the laser used by the carbon dioxide laser device is greater than the power of the laser used when constructing the cutting groove along the transverse cutting line (302) or along the longitudinal cutting line (303).

8. The method for excavating a connecting passage by using a carbon dioxide laser device according to claim 7, characterized in that, In step S3, the depth of the cutting groove is 200 to 400 mm; when constructing the cutting groove along the circumferential cutting line (301), the laser power used is 11 to 14 kW; when constructing the cutting groove along the transverse cutting line (302) or the longitudinal cutting line (303), the laser power used is 8 to 10 kW.

9. The method for excavating a connecting passage by using a carbon dioxide laser device according to claim 7, characterized in that In step S3, the following steps are further included: after constructing the cutting groove along the circumferential cutting line (301), first perform frozen soil disturbance construction, and then construct the cutting groove along the transverse cutting line (302) or the longitudinal cutting line (303); when performing frozen soil disturbance construction, use the carbon dioxide laser device to irradiate the surface of the frozen soil located within the closed circle B surrounded by the circumferential cutting line (301); the laser power used during frozen soil disturbance construction is 4 to 6 kW.

10. The method for excavating a connection tunnel by using a carbon dioxide laser device according to claim 1, wherein After each completion of step S4, the following steps are immediately carried out: remove the frozen soil body within the excavation contour line (2), and perform support construction on the tunnel wall of the exposed connection tunnel (5).

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