Luliangshan Tunnel is the key control project of Taizhongyin Railway. The tunnel is 20738m long and is the longest tunnel of Taizhongyin Railway. It is also the second longest tunnel in China. The tunnel DK129+255 to the exit DK139+930 is under construction by the China Railway Third Bureau. The total length is 10675m. The tunnel is designed as a double-hole tunnel. The left and right lines are two parallel single-line tunnels with a spacing of 30m. #,4#,5# Three inclined wells, the average slope of the inclined shaft is 12%, and the 3#, 4# inclined wells intersect with the Luliangshan tunnel at the right line mileage DK132+035, DK132+140.71, respectively. For the 1783m, 1777m, 5# inclined well and Luliangshan tunnel at the right line mileage DK135+770, the length of the inclined shaft is 1190m. The tunnel is a Class II, III, IV, V and VI strengthening surrounding rock, tunnel Mainly through shale, limestone, sandstone layer, the exit section is a collapsible yellow land section, crossing the Qingyin Expressway in the DK139+810~DK139+690 section, the minimum buried depth is 16m, and crossing the Wu in DK137+940~DK138+160 The urban fault zone and the fault zone are affected by the thrust fault (F27) of Shangfeng Village-Wucheng-Hwanwan Village. The lithology of the fault is quartz sandstone, the granitic gneiss is sandwiched by pegmatite veins, and the rock mass is broken. The granitic gneiss core is sand-like, the stability of the rock mass is very poor, and the limestone rock mass under the fault is broken. The groundwater types in this area include Quaternary pore diving, bedrock fissure water, karst water, and fault water. The Quaternary pore diving mainly occurs in the valleys or hillsides, and in the Quaternary loose deposits on the mountain beams, small spring water flows out of the valleys.

2 overall construction organization deployment

2.1 Project scope and work area distribution

Combined with the geological characteristics of the project, the distribution of surrounding rock, the construction period and the difficulty of construction, the tunnel adopts a multi-port parallel construction organization plan, which is started in three construction areas. The first working area is responsible for the DK137+930~DK139+930 section. This section belongs to V, VI grade is strengthened, the geology is complex, belongs to the yellow land section, and passes through the high-risk operation area of ​​Qingyin Expressway and Wucheng Fault Zone. Face-to-face approach. It is difficult to construct the Qingyin high-speed construction under construction stage, which may restrict the overall construction period. After the scheme comparison, add 6# horizontal hole, the cross hole length is 150m, intersect with the left line and DK139+560, skip the lower blue silver In the high-speed section, the two-way four working faces are used to ease the construction pressure; the second working area is responsible for the 5# inclined well and the positive hole DK134+200～DK137+930. The section is II, III, IV, and the surrounding rock is mainly It is dominated by braided limestone, sandstone and shale. After the inclined well enters the positive tunnel, the two-way four working faces are used for excavation. The stone direction is only applied to the Wucheng fault zone. Considering the Wucheng fault zone, large Water inrush, mudline and positive hole height difference, drainage and drainage difficulties, Wucheng fault zone construction by a work area, drainage can be discharged through 6# horizontal hole; Sangong District is responsible for 3#, 4# inclined well and positive The left and right lines of the hole are 129+255~134+200. The positive section belongs to the II and III surrounding rocks. The rock is mainly composed of braided limestone and sandstone, and the surrounding rock has good integrity. 3#, 4# inclined shaft is the main auxiliary inclined shaft, the spacing is 30m.3# The inclined shaft intersects the right line of the right hole DK132+035, and the single port is 2780m in the direction of Taiyuan. In the early stage, consider adding a deviated well in the direction of Taiyuan to relieve the positive The construction pressure of the cave, on-site field inspection, and the selection of a location as the location of the inclined well, set a preliminary plan. The slope of the inclined well has a large slope and can only be transported by rail. After accounting, the cost is too large and uneconomical. #斜井正洞 Left and right lines can only use one-way two working faces. The 4# inclined well and the right line positive hole design intersect at DK132+140.71. In the construction stage, the 4# construction pressure is considered to be relieved, and the 4# inclined well is rerouted. After the line is changed, the right line and the right hole are intersected at DK132+966. The length is 1610m, and the inclined well enters the positive hole and adopts the two-way four working surface.

2.2 Determination of construction progress indicators

According to the overall engineering task division, combined with the geological conditions of the tunnel and the construction level of the tunnel, the main attack direction and the secondary attack direction are determined for each working port in the pipe section. The resource allocation in the main attack direction preferentially meets the construction requirements, the auxiliary attack direction, and the resource allocation. It can be used for deployment without affecting the main direction of construction. The direction of Taiyuan in the first working area is the main direction of attack. The direction of the 5# Zhengdong in the second working area is the direction of the main attack. The direction of Taiyuan is the direction of the sub-attack. The direction of the 3# Zhengdong in the Sangong District is the main direction of attack, and the direction of the 4# in the Sangong District is the direction of the attack. The direction of Taiyuan is the direction of the offensive. According to the surrounding rock conditions and the current tunnel construction level, the progress indicators of the surrounding rock at all levels are determined: the main attack direction, the V-level and VI-level strengthening surrounding rock excavation is 70m/month, the IV-level surrounding rock excavation is 100m/month, and the third-level surrounding rock excavation 160m/month, Class II surrounding rock excavation 180m/month; Sub-attack direction: Grade IV surrounding rock excavation 85m/month, Class III surrounding rock excavation 120m/month, Class II surrounding rock excavation 135m/month. According to this calculation, the completion of the entire tunnel can be ensured within 3 days of the total construction period.

2.3 Configuration of major mechanical equipment

2.3.1 Air compressor configuration

The air compressor configuration is determined according to the construction work surface and the main and auxiliary attack directions. The main attack direction configuration is configured according to the single work surface construction, and the two work surfaces in the auxiliary attack direction are configured according to the work surface. For the long tunnel, the air compressor adopts the hole-in scheme, and both adopt the screw air compressor. The water-cooled air compressor has a small space in the cave, and it is not suitable to set the cooling pool. After 1km, the air compressor has serious wind damage, and the air compressor moves once every 1km, and the corresponding power transformer is shifted.

2.3.2 Lining trolley configuration

Inverted arches and linings are the key to ensuring the safety of the tunnel structure. In the tunnel construction, the step relationship between the surrounding rock face and the inverting arch and the lining is specified. The tunnel construction always adheres to the construction operation concept of excavation, inverting arch and lining process. According to the overall construction and deployment, I have a total of 12 lining trolleys in the pipe section, and one lining trolley for each of the two working faces in the work area, a total of two. Because the 6# horizontal hole is added to the Qingyin Expressway, after the horizontal hole enters the main hole, two sets of lining simple gantry are added to ensure that the lining of each face is followed up synchronously to ensure the safety of the tunnel construction. In the 2# Zhengdong pipe section of the 2nd Industrial Zone, after the inclined well enters the main hole, the construction is organized by the excavation method of the four working surfaces of the left and right lines, and one working surface of the lining trolley is used for a total of four.

Sangong District 3# Zhengdong Taiyuan direction two working faces, one lining trolley, one set, two sets, three working area 4# positive hole, the inclined well enters the main hole and is constructed by four working faces of construction organization, lining There are 1 set of trolleys per work surface, a total of 4 sets. Considering the construction progress index of surrounding rock at all levels and the current level of lining construction, when the lining in the construction can not meet the specified step relationship, the lining scheme is adopted, and the lining of the lining is carried out to meet the step relationship to ensure the safety of the tunnel construction. Unmanufactured lining sections will be constructed using a lining simple gantry. The length of the single-port excavation in the 3# Zhengdong Taiyuan area of ​​the Sangong District is 2780m, and the surrounding rock is mainly II. According to the current lining trolley configuration, the lining construction will lag, and the lining scheme is adopted in the construction to ensure the safety of the tunnel structure space. After the completion of the lining of 3#, 4# Zhengdong, the 2 lining trolleys of the 4# Zhengdong Taiyuan direction are moved to the direction of Taiyuan, Taiyuan, and the lining of the lining lining section is not applied, which can speed up the tunnel. Lining speed.

3 tunnel construction plan

Tunnel construction is a comprehensive system engineering, and a reasonable auxiliary operation plan is the prerequisite for ensuring the overall advancement of the tunnel.

3.1 Determination of the scheme of inclined shaft section

The section of the inclined shaft of Luliangshan Tunnel is designed to be 5m×5.68m (width×height). The transportation adopts trackless transportation, and a wrong car platform is set in 250m. According to the design section, the vehicle can only be used on a one-way street. It cannot be turned inside the hole. It can only be reversed from the hole to the face. In addition, the height of the tanker is higher than that of the exiting tank, and the height of the tanker is 3.8m. The ventilation inside the cave is supplied with air by a ventilating cloth with a diameter of 1.5m. The section cannot meet two or three ventilating fabrics at the same time, and the section is small and ventilated. Difficulties in exhausting smoke. In view of the existing problems, we have changed the section of the inclined well to 6.5m×6.43m (width×height), and set a reverse tunnel at 200m to cancel the wrong platform and solve the problem caused by the small section of the inclined shaft in the exit and ventilation. A series of questions.

3.2 Construction power supply plan

The construction of long tunnels, the importance of the choice of power supply scheme is very prominent, and reliable power supply is the basic guarantee for the normal operation of all equipment in the tunnel, resulting in great economic benefits. The main electrical equipment of the tunnel is: the lighting in the tunnel, the axial flow fan and the jet fan for construction ventilation, the air compressor, the pump, the pump, etc., the construction of the inclined shaft in advance, and the consideration of the power supply scheme for the long tunnel construction is not considered. Zhou, directly using the local power and generator combined power supply mode, with the extension of the inclined shaft excavation, the tunnel drainage equipment increased, the electric load increased, the existing power supply system can not meet the electricity requirements, another place 871 west In the eighth phase of the prospecting project in 2010, the power supply was unstable, the voltage was low, and the equipment could not operate normally, which directly restricted the progress of the project. For the problems existing in the power supply scheme, the power supply scheme of the long tunnel is re-adjusted. According to the design data and the overall construction plan, the total electricity consumption of the three work areas during the peak period of power consumption is 8000-9000kW. The plan is adjusted to: 24km from the 35kV substation of Shitianjiahui to the exit, to build a simple 35/10kV Substation, erecting 8km line to each inclined wellhead as a construction power supply line. Ventilation and other equipment use electricity in the cave, and all three work areas adopt high-voltage (power) hole-in scheme. The long tunnel is over 1000m, and the voltage loss is too large due to the long distance of the power supply. The main transformer is used in the cave (pump station, air compressor) to set the voltage regulator. Due to the large amount of water in the Luliangshan tunnel, the pumping equipment can not stop working due to the power outage. The generators are arranged at the pumping stations at the various levels in the cave. When the power is cut off or the line is repaired, the pumping equipment is normal. After practice, the power supply scheme is feasible. If the inclined shaft is constructed according to this scheme before construction, the construction progress of the project can be accelerated and a large amount of funds can be saved.

3.3 ventilation plan

The construction working environment is very important in the tunnel construction, and the ventilation conditions directly restrict the progress of the project. Ventilation of long tunnels is currently a technical problem. Before the construction period starts, the selection of the ventilation scheme must be carefully considered. The selection of the ventilator, the diameter of the duct, the number of ducts to be laid, etc. must be strictly calculated and checked before implementation. For the construction of long tunnels, a phased ventilation scheme ensures the quality of the air inside the cave. The ventilation plan of the Luliangshan tunnel is implemented in three stages: in the first stage, before the positive hole is penetrated between 3#, 4# or between 4# and 5#, the axial flow fan is arranged from each inclined wellhead to adopt press-in ventilation. The axial flow fan adopts 2×110kW (one ventilation pipe), and adopts a 1.5m diameter air duct cloth, which can open double high and low low, and the air supply distance is 2200～2300m. If the single port excavation exceeds the conveying distance, then the 55kW shaft is adopted. The flow fan is supplied in series. 3# Inclined wells are provided with 2 air ducts from the hole, respectively, and the wind is sent to the right and left lines of Zhengyuan Taiyuan. 4#, 5# inclined wells are respectively arranged in the inclined wellhead to provide 3 wind tunnels to the main tunnel for air supply. The line is a cross-operation, with a bellows for the left and right ventilation, and the other two for the left and right lines of the main attack direction. In the second stage, after 3#, 4# or between 4# and 5#, the 4# inclined shaft is used as the air inlet, the 3#, 5# inclined shaft fan is moved to the positive hole, and the 3# fan is moved. To the third line of the main hole, the left and right lines of the stone are separated from the direction of the stone, and the wind is sent to the left and right lines of the 3# main hole. The 5# fan is moved to the left and right lines of the Sanyuankou Taiyuan, and the wind is sent to the left and right lines of the 5#. , 3 #, 5 # respectively as the air outlet. In the third stage, the length of the single-port excavation in the Taiyuan direction of the 3# inclined well is 2780m. After the tunnel is drilled to 2200m, the ventilation environment is poor, and the combination of tunnel ventilation and mixed ventilation is adopted. The axial flow fan of the positive hole away from the stone is forwarded 840m to the direction of Taiyuan, and is located at the second horizontal channel of Sanchakou to Taiyuan. The left line is the air inlet, the right line is the air outlet, and the left line is the axial fan. Hang the curtain on the front, close the whole hole, connect the air inlet of the right-line axial fan to the horizontal channel, and block the horizontal channel at the right line. If the air quality of the right line is poor, then the horizontal channel is in the position. 20m away from the stone direction, set up a 110kW axial fan, connect the 1.2m diameter air duct cloth to the 3# inclined shaft, and pump dirty air. The first working area is constructed by the exit end of the tunnel. The ventilation is directly arranged in the tunnel at the left and right openings.

3.4 Drainage scheme

The groundwater types in the Luliangshan tunnel include Quaternary pore diving, bedrock fissure water, karst water, and fault water. The Quaternary pore diving mainly occurs in the valley or hillside, and small spring water flows out in the valley. The carbonate rocks in the area are widely distributed, with large thickness, joints, fissures and karst development. They are the main water-bearing rock series and have more spring water. The design data reveals that the fissure water of the bedrock is relatively developed, and the permeability coefficient is 0.1m/d. During the tunnel construction, the 3#, 5# fissure water develops, and the water output per hole exceeds 400m3 / h. For the long tunnel, the inclined well The difference between the height of the hole and the hole is 200m. It is necessary to eliminate the water on the working surface in the shortest time and become a technical problem of tunnel construction. Through the exploration and practice of drainage in the construction of Luliangshan tunnel, a complete set of construction drainage scheme is formed. . The drainage in the inclined shaft is: the average slope of the inclined shaft of the tunnel is 12%, and a pumping station is set at 550-600m in the inclined well. The pumping pool capacity of the pumping station is about 400m3. The inclined well pumping station of Luliangshan tunnel hits one side of the inclined well. The guide hole is 20m long, 6m wide and 3.5m deep. The top surface of the pool is 50cm higher than the bottom of the inclined shaft. The platform is placed above the pool to place the water pump. The pump adopts a 55kW slurry pump. The 55kW slurry pump has a design head of 80m and a flow rate of 80m3 / h. The drainage pipeline uses a Steel Pipe with a diameter of 200mm. The steel pipe with a diameter of 200mm allows a flow rate of 240m3 / h. One steel pipe is connected to three 55kW slag. Slurry pump. The pumping station and the pumping station are pumped out to the outside of the cave. According to the size of the water output, the pipeline and the 55kW slurry pump are arranged reasonably. 3#, 4# inclined wells adopt three-stage pumping, and 5# inclined wells adopt second-stage pumping. The drainage in the positive hole is: the slope of the positive hole design is 11‰, and when the slope is drained, the pool is set at the position of the 420m horizontal tunnel of the main hole. The pool is set in the middle of the hole, 8m long, 2m wide, 2m deep, the top surface of the pool Consistent with the tunnel tunnel bottom surface, the steel and steel plates are laid on top to facilitate the passing of the vehicle. The 13kW sewage pump is used for staged pumping, and finally discharged into the first-stage pumping station in the inclined shaft, and then discharged out of the hole step by step through other pumping stations in the inclined shaft. The 13kW sewage pump has a head of 40m and a flow rate of 70m3 / h. A drain pipe with a diameter of 200mm is arranged between the pools in the main tunnel, and a 13kW sewage pump is connected to one drain pipe. The main tunnel is drained along the slope, and drainage is provided on both sides of the main hole. The ditch is self-flowing and accumulating in the pool of the first-stage pumping station, and then pumped out to the inclined well through the pumping stations at all levels in the inclined shaft.

4 Conclusion

(1) The construction organization and perfect construction plan for the construction of long tunnels, except for the consideration of cost and construction period, it is more important to ensure the rapid tunneling of auxiliary tunnels, such as ventilation, exhaust, drainage, etc. Prerequisite guarantee for rapid excavation.

(2) Through the construction of the Luliangshan tunnel, the technical difficulties in the construction of the long tunnel are mainly in the power supply scheme, ventilation and exhaust, drainage scheme, etc. In the selection of the scheme, it is necessary to consider the unforeseen factors in the tunnel construction. The scheme is reasonable and implementable. Strong, to prevent the lack of technical solutions and imperfections, causing unnecessary losses to the subsequent construction.

9712010, No. 8 Western Exploration Project

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