A downslope drainage and sewage separation system for double-hole highway tunnels in karst geological areas

Abstract

The utility model discloses a downslope drainage and sewage diversion system for a double-hole highway tunnel in a karst geological area, comprising a sewage sump. The downslope drainage and sewage diversion system for the double-hole highway tunnel in a karst geological area utilizes a certain transverse hole between two main holes of the double-hole extra-long highway tunnel to separate clean water and sewage, and discharges the clean water and sewage from different main holes respectively outside the tunnel, firstly arranges a two-stage sedimentation tank in the tunnel to preliminarily screen out solid pollutants with large particle sizes in the sewage, and reduces the subsequent treatment pressure of the sedimentation tank outside the tunnel, fully utilizes the central drainage ditch already in the original design, does not add a large number of drainage pipelines and pumping equipment, fully utilizes the transverse slope height difference generated by the construction time sequence between the concrete pouring process of the invert filling (leveling layer) and the pouring process of the trench wall of a cable trench on one side, and introduces the construction wastewater into the temporary cable trench that has not been poured as a sewage side ditch.

Description

Technical Field

[0001] The utility model relates to the technical field of sewage cleaning and diversion in highway tunnels, in particular to a downslope drainage sewage cleaning and diversion system for a double-hole highway tunnel in a karst geological area. Background Art

[0002] As my country's highway network construction gradually focuses on the western mountainous provinces, the proportion of extra-long tunnels with a length of more than 3,000 meters and involving working conditions in karst karst landforms is increasing. Highway tunnel construction under such working conditions often faces the following problems: large tunnel water inflow, long construction period, many processes that generate sewage, high drainage water quality standards adjacent to receiving water bodies, and the inability to build a large sewage treatment plant outside the tunnel in the mountainous environment. Therefore, the wastewater generated by each process during tunnel construction is collected from the source, separated from the clear water gushing out of the surrounding rock of the completed section through reasonable drainage channels and pipeline layout in the tunnel, and discharged out of the tunnel using the natural height difference of the longitudinal slope when the tunnel is excavated along the slope end. This can reduce the scale of tunnel wastewater treatment from the source and reduce the difficulty of treatment.

[0003] The existing relatively advanced tunnel wastewater treatment methods, such as evaporation concentration, ion exchange, membrane separation, flotation, biofilm, etc., have long treatment times and high costs, and cannot cope with the up to tens of thousands of cubic meters of water per day generated by mountain tunnels that cross karst geological zones. In other cases of sewage diversion and drainage engineering projects in extra-long mountain tunnels, most of them are based on the fact that the tunnels are equipped with inclined shafts and drainage tunnels, so there is a wide range of drainage schemes to choose from. At the same time, for extra-long tunnels that are more than ten kilometers long, cross karst geological zones, and are not designed with inclined shafts, parallel pilot tunnels, drainage tunnels and other auxiliary tunnels, there is currently a lack of clear and unified sewage diversion and drainage system design during construction in China.

[0004] Therefore, we proposed a downslope drainage and sewage diversion system for double-hole highway tunnels in karst geological areas to solve the problems raised above. Summary of the invention

[0005] The utility model provides a downhill drainage and sewage diversion system for a double-hole highway tunnel in a karst geological zone, which solves the existing relatively advanced tunnel wastewater water quality treatment methods mentioned in the above background technology, such as: evaporation concentration method, ion exchange method, membrane separation method, flotation method, biofilm method, etc., which have long processing time and high cost, and cannot cope with the up to tens of thousands of cubic meters of water per day generated by mountain tunnels crossing the karst geological zone. In other cases of sewage diversion and drainage engineering projects in extra-long mountain tunnels, most of them are based on the situation that the tunnel is equipped with inclined shafts and drainage holes, and there is a large room for drainage scheme selection. At the same time, for extra-long tunnels that have the characteristics of more than ten kilometers in length, crossing the karst geological zone, and no inclined shafts, parallel guide tunnels, drainage holes and other auxiliary tunnels, there is currently a lack of clear and unified sewage diversion and drainage system design during construction in China.

[0006] The utility model provides the following technical scheme: a downslope drainage and sewage diversion system for a double-hole highway tunnel in a karst geological area, comprising a sewage collection pit, a central drainage ditch is opened on the side of the sewage collection pit, a sewage side ditch is opened on the side of the sewage collection pit, a pumping component is commonly connected between the sewage collection pit and the sewage side ditch, a cross-hole drainage channel is commonly opened between the two central drainage ditches, a baffle is fixedly installed at the junction of the central drainage ditch and the cross-hole drainage channel, a two-stage tunnel sedimentation tank is opened at one end of the sewage side ditch, a five-stage tunnel sedimentation tank is opened at one end of the central drainage ditch, a leveling layer is laid on the upper end of the central drainage ditch, and the side of the central drainage ditch is connected to a tunnel bottom transverse drainage pipe.

[0007] As an optional solution described in the utility model, the sewage collection pit is located near the left and right faces of the highway tunnel, and the central drainage ditch is opened in both the left and right tunnels.

[0008] As an optional solution described in the utility model, the sewage ditch is set in the left and right holes close to one side wall, and the pumping assembly includes a pumping device and a drainage pipeline.

[0009] As an optional solution described in the utility model, the horizontal tunnel drainage channel utilizes any horizontal tunnel space excavated in the tunnel and is grooved on the ground to connect the central drainage ditch of the left and right tunnels.

[0010] As an optional solution described in the utility model, the baffle is arranged at the intersection of the central drainage ditch of the left tunnel and the drainage channel of the horizontal tunnel, and the two-level sedimentation tank inside the tunnel and the five-level sedimentation tank outside the tunnel can screen out large-sized solid particle suspensions and a large amount of silt.

[0011] As an optional scheme described in the utility model, the leveling layer is a filling layer that has been filled behind the excavation and initial support operation section and has a transverse slope inclined toward one side of the sewage ditch. The tunnel bottom transverse drainage pipe is buried in the concrete of the leveling layer and is a corrugated pipe for connecting to the drainage blind pipe inside the second lining, and discharges the clean water gushing out of this part of the surrounding rock into the central drainage ditch through the tunnel bottom transverse drainage pipe.

[0012] The utility model has the following beneficial effects:

[0013] 1. Reduce the total scale of wastewater treatment. During the survey and design phase of this tunnel, it was predicted that the water inflow during the flood season would be 98,373 m3 / d, and during the normal water season would be 73,798 m3 / d; during the actual construction period, the total water inflow at the downslope drainage end was measured to be about 60,000-80,000 m3 / d; after the system was used to separate the clean and dirty water, the amount of sewage entering the sedimentation tank outside the tunnel was reduced to about 30,000 m3 / d, reducing the scale of wastewater treatment by 50%-62.5%.

[0014] 2. Make full use of the existing central drainage ditch in the original design, and only add sewage side ditches and small pumping equipment between the diversion tunnel and the heading face, which saves materials, equipment and personnel, reduces the total project cost, and reduces interference with other processes.

[0015] 3. Under the unfavorable condition that the average daily water inflow of the tunnel far exceeds that of most of the highway tunnels under construction in China, the results of monthly water quality sampling and inspection after treatment in the sedimentation tank outside the tunnel show that its pH value, suspended solids (SS), total nitrogen, petroleum and other indicators have reached the water discharge indicators in various specifications such as "Highway Environmental Protection Design Code" (JTG B04-2010), "Surface Water Environmental Quality Standard" (GB 3838-2002), and "Integrated Sewage Discharge Standard" (GB 8978-1996), which is consistent with the national tone of coordinating engineering construction with environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0017] Figure 2 It is a structural schematic diagram of the utility model.

[0018] In the figure: 1. Sewage collection pit; 2. Central drainage ditch; 3. Sewage side ditch; 4. Pumping assembly; 5. Cross-tunnel drainage channel; 6. Baffle plate; 7. Two-level tunnel sedimentation tank; 8. Five-level tunnel sedimentation tank; 9. Leveling layer; 10. Tunnel bottom horizontal drainage pipe. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model. Example

[0020] See also Figure 1 - Figure 2 A down-slope drainage and sewage diversion system for a double-hole highway tunnel in a karst geological area comprises a sewage collection pit 1, a central drainage ditch 2 is opened on the side of the sewage collection pit 1, a sewage side ditch 3 is opened on the side of the sewage collection pit 1, a pumping assembly 4 is commonly connected between the sewage collection pit 1 and the sewage side ditch 3, a cross-hole drainage channel 5 is commonly opened between the two central drainage ditches 2, a baffle plate 6 is fixedly installed at the junction of the central drainage ditch 2 and the cross-hole drainage channel 5, a two-stage tunnel sedimentation tank 7 is opened at one end of the sewage side ditch 3, a five-stage tunnel sedimentation tank 8 is opened at one end of the central drainage ditch 2, a leveling layer 9 is laid on the upper end of the central drainage ditch 2, and a tunnel bottom transverse drainage pipe 10 is connected to the side of the central drainage ditch 2.

[0021] The sewage collection pit 1 is located near the left and right faces of the highway tunnel, and the central drainage ditch 2 is opened in the left and right tunnels.

[0022] The sewage ditch 3 is arranged in the left and right holes near one side wall, and the pumping assembly 4 includes a pumping device and a drainage pipeline.

[0023] The transverse tunnel drainage channel 5 utilizes any transverse tunnel space excavated in the tunnel and is grooved on the ground to connect the central drainage ditches 2 of the left and right tunnels.

[0024] The baffle plate 6 is arranged at the intersection of the central drainage ditch 2 of the left tunnel and the drainage channel 5 of the horizontal tunnel. The sedimentation tank 7 in the two-level tunnel and the sedimentation tank 8 outside the five-level tunnel can screen out large-size solid suspended particles and a large amount of sediment.

[0025] The leveling layer 9 is a filling layer that has been filled behind the excavation and initial support operation section and has a transverse slope inclined toward the sewage ditch 3. The tunnel bottom transverse drainage pipe 10 is buried in the concrete of the leveling layer 9. It is generally a corrugated pipe and is used to connect to the drainage blind pipe inside the secondary lining. The clean water gushing out of this part of the surrounding rock is discharged into the central drainage ditch 2 through the tunnel bottom transverse drainage pipe 10.

[0026] This clean and dirty water diversion system is suitable for double-hole, double-track extra-long highway tunnels designed with cross holes, excavated by drilling and blasting method, and with the tunnel opening excavated in an uphill direction.

[0027] In this scheme, the wastewater generated during tunnel construction can be discharged into the sewage ditch 3 in two different ways.

[0028] The first type: The sewage collection pit 1 is set near the face in the plan view, which is used to collect sewage generated in the drilling and charging, blasting, slag removal, initial support, secondary lining and invert casting processes. A sewage collection pit 1 is set near the left and right tunnel faces. The tunnel section in this section is large. Because the invert and leveling layer have not been cast or are in the process of casting, their position is lower than the sewage ditch at the rear. Therefore, the wastewater generated by the above processes can only be collected through the sewage collection pit 1 first, and then the sewage is pumped from the collection pit into the sewage ditch at the rear using small pumping equipment and pipelines.

[0029] The second type: from the two-level sedimentation tanks 7 in the left and right main tunnels to the front position where the leveling layers 9 of the two tunnels are poured and the central drainage ditch 2 is also completed, a small amount of sewage may be generated on the ground in this section due to factors such as water sprinkling in the tunnel to reduce dust, slag dropping and slurry spreading by operating machinery such as slag trucks and tank trucks. As shown in the cross-sectional view, the bottom and wall of the cable trench position on one side of the original design have not been poured at this time (the bottom of the cable trench should be higher than the top surface of the leveling layer concrete after pouring), but during the pouring of the leveling layer, a groove is deliberately left on one side for the subsequent pouring of the cable trench (that is, the leveling layer concrete is deliberately not poured at this position). This temporary groove reserved for the cable trench construction is fully utilized by this system as a temporary sewage ditch 3. When pouring the leveling layer, it should be noted that the side close to the sewage ditch 3 should be filled slightly lower, and the side away from the sewage ditch 3 should be filled slightly higher, thereby forming a horizontal slope inclined toward the sewage ditch 3, so that the surface sewage belonging to the second case mentioned above can be introduced into the sewage ditch 3.

[0030] The clean water source of this system is mainly the surrounding rock water gushing from the section where the lining waterproof layer and the secondary lining have been constructed. As shown in the cross-sectional view, the tunnel bottom transverse drainage pipe 10 is buried in the concrete of the leveling layer 9 as a corrugated pipe, which is used to connect with the drainage blind pipe inside the secondary lining (the drainage pipelines inside the lining waterproof layer and the secondary lining are not original, so they are not drawn), and the clean water gushing from this part of the surrounding rock is discharged into the central drainage ditch 2 through the tunnel bottom transverse drainage pipe 10.

[0031] The sewage in the above two cases, after being discharged into the sewage ditch 3, flows into the two-stage cave sedimentation tank 7 for pretreatment. A two-stage cave sedimentation tank 7 is set up in each left and right cave, which can screen out large-size solid suspended matter and a large amount of silt. The two-stage cave sedimentation tank 7 should be set not far in front of the horizontal cave where the drainage channel connecting the left and right caves is located, and the impurities at the bottom of the pond must be cleaned regularly. The sewage treated by the two-stage cave sedimentation tank 7 of the left and right caves is pumped and discharged into the central drainage ditch 2 behind the baffle 6 in the plan view through the pumping equipment and pipelines, and is discharged to the five-stage cave sedimentation tank 8 through the central drainage ditch 2 of the left cave for further treatment. The five-stage cave sedimentation tank 8 should also regularly clean and transport the impurities such as silt and sediment at the bottom of the pond. If necessary, water quality treatment methods such as acid adjustment and flocculation can be added according to the actual situation of different engineering projects. The actual water quality of the engineering project on which this system relies has reached the standard after being treated in the five-stage cave sedimentation tank 8, so it will not be repeated.

[0032] The horizontal tunnel selected as the location of the horizontal tunnel drainage channel can be selected according to the actual situation of the project (it can be a pedestrian cross passage, a vehicle cross passage, a tunnel connecting passage, etc.), and the overall distribution characteristics of the water-rich surrounding rock in the tunnel site area, the interference with other processes as little as possible, and the passage of operating vehicles and mechanical equipment should be considered comprehensively. This system selects a pedestrian cross passage as the location of the horizontal tunnel drainage channel 5. A baffle 6 is set at the intersection of the central drainage ditch 2 of the left tunnel (sewage discharge tunnel) and the horizontal tunnel drainage channel 5, and the clean water in the central drainage ditch 2 of the left tunnel (sewage discharge tunnel) is diverted from the front of the baffle 6 to the horizontal tunnel drainage channel 5, and flows into the central drainage ditch 2 of the right tunnel (clean water discharge tunnel), and is discharged out of the tunnel together with the clean water of the right tunnel (clean water discharge tunnel). Since the source of clean water is mainly the gushing water of the tunnel surrounding rock, it only flows through the longitudinal and transverse blind pipes pre-buried in the lining structure, the tunnel bottom transverse drainage pipe 10 and the central drainage ditch 2, and is not polluted by any process, so it can be directly discharged into the surrounding environment. It should also be noted that: this plan uses the left tunnel as a sewage drainage tunnel and the right tunnel as a clean water drainage tunnel because the design elevation of the left tunnel of this tunnel is higher than that of the right tunnel. Therefore, the cross tunnel diversion channel 5 can directly lead the clean water in the central ditch of the left tunnel to the central ditch of the right tunnel due to the height difference. In future application and promotion, the specific circumstances of other engineering cases should be used to select which side to use as the clean water discharge tunnel and which side to use as the sewage discharge tunnel.

[0033] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A downslope drainage and sewage diversion system for a double-hole highway tunnel in a karst geological area, comprising a sewage collection pit (1), characterized in that: A central drainage ditch (2) is provided on the side of the sewage sump (1), a sewage side ditch (3) is provided on the side of the sewage sump (1), a pumping assembly (4) is commonly connected between the sewage sump (1) and the sewage side ditch (3), a transverse tunnel drainage channel (5) is commonly provided between the two central drainage ditches (2), a baffle plate (6) is fixedly installed at the junction of the central drainage ditch (2) and the transverse tunnel drainage channel (5), a two-stage tunnel sedimentation tank (7) is provided at one end of the sewage side ditch (3), a five-stage tunnel sedimentation tank (8) is provided at one end of the central drainage ditch (2), a leveling layer (9) is laid on the upper end of the central drainage ditch (2), and a tunnel bottom transverse drainage pipe (10) is connected to the side of the central drainage ditch (2).

2. The downslope drainage and sewage separation system for a double-hole highway tunnel in a karst geological area according to claim 1 is characterized by: The sewage collection pit (1) is located near the left and right faces of the highway tunnel, and the central drainage ditch (2) is opened in both the left and right tunnels.

3. The downslope drainage and sewage separation system for a double-hole highway tunnel in a karst geological area according to claim 2 is characterized by: The sewage ditch (3) is arranged in the left and right holes close to one side wall, and the pumping assembly (4) comprises a pumping device and a drainage pipeline.

4. The downslope drainage and sewage separation system for a double-hole highway tunnel in a karst geological area according to claim 3 is characterized by: The transverse tunnel drainage channel (5) utilizes any transverse tunnel space excavated in the tunnel and is grooved on the ground to connect the central drainage ditch (2) of the left and right tunnels.

5. The downslope drainage and sewage separation system for a double-hole highway tunnel in a karst geological area according to claim 4 is characterized by: The baffle plate (6) is arranged at the intersection of the central drainage ditch (2) of the left tunnel and the drainage channel (5) of the horizontal tunnel. The two-stage in-tunnel sedimentation tank (7) and the five-stage out-tunnel sedimentation tank (8) can screen out large-size solid suspended matter and a large amount of sediment.

6. The downslope drainage and sewage separation system for a double-hole highway tunnel in a karst geological area according to claim 5 is characterized by: The leveling layer (9) is a filling layer that has been filled behind the excavation and primary support operation section and has a transverse slope inclined toward one side of the sewage ditch (3). The tunnel bottom transverse drainage pipe (10) is buried in the concrete of the leveling layer (9) and is a corrugated pipe used to connect to the drainage blind pipe inside the secondary lining and discharge the clean water gushing out of this part of the surrounding rock into the central drainage ditch (2) through the tunnel bottom transverse drainage pipe (10).

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