Longitudinal and transverse drainage system of long-distance water conveyance canal

Abstract

The invention relates to a longitudinal and transverse drainage technology about water seepage in the technical field of water delivery in soft rock areas, in particular to a longitudinal and transverse drainage system of a long-distance water delivery canal. The longitudinal drainage is arranged at the bottom of the channel along the longitudinal line of the channel and is used for collecting seepage water in a channel base; the transverse drainage is arranged along the transverse line, a water inlet of the transverse drainage is connected with the longitudinal drainage, and the gradient of the transverse drainage is larger than that of the longitudinal drainage; wherein when the self-flowing condition is met, water is drained to a low-lying position through a water outlet for transverse drainage; and when the self-flowing condition is not met, the water outlet for transverse drainage is connected with a water collecting well, and water is drained into the water collecting well. According to the method, mudstone replacement and filling are conducted through the channel, a channel bottom longitudinal and transverse drainage system is additionally arranged, water pumping and drainage are conducted all the year round in the channel water running period and the water cut-off period, gap water existing in a channel bed soil body after membrane water seepage and water cut-off is drained out of a channel bed, it is guaranteed that the channel bed is relatively dry before winter, channel frost heaving resistance design is not conducted, and investment is saved.

Description

Technical Field

[0001] The invention relates to a longitudinal and transverse drainage technology for water seepage in the technical field of water delivery in soft rock areas, and in particular to a longitudinal and transverse drainage system for a long-distance water delivery channel. Background Art

[0002] According to the geological conditions during the construction of the main canal, the main canal section 20+000~45+000 is concentrated with swelling mudstone, which is divided into strong swelling, medium swelling and weak swelling mudstone according to the swelling force. The underground water level in this section of the canal is buried deeper than 200m. During the construction, only the mudstone on part of the canal slope and bottom was replaced, and no canal drainage system was built.

[0003] During the operation of the main canal, deformation of the canal embankment and landslides caused by softening of mudstone occurred from time to time. According to the geological conditions revealed on site, in addition to the mudstone distributed in the entire section of the canal, the landslides also occurred in the sections where the mudstone was distributed in strips or nests at the bottom of the canal or near the foot of the slope. Due to multiple landslides in the 20+000~42+000 section of the main canal, more than 80% of the canal sections have completed full-section replacement filling, with a replacement filling thickness of 1.5m for the slope and 1m for the bottom of the canal. The replacement filling material uses the nearby gravel-bearing white sandstone, and no drainage system is set up at the bottom of the canal.

[0004] Since there is no drainage system at the bottom of the channel, the permeability coefficient of the replacement filling material is relatively large. As the operation time of the channel increases, the saturated area of ​​the mudstone foundation of the channel bed continues to increase. In recent years, landslides have occurred again in the section of the main canal from 20+000 to 45+000 that had been treated in the past.

[0005] Therefore, it is necessary to set up longitudinal and transverse drainage systems on the main canal. Summary of the invention

[0006] Under the above background, the present invention provides a longitudinal and transverse drainage system for a long-distance water transfer channel to solve the problem that water cannot be drained due to longitudinal drainage based on the longitudinal slope. On the one hand, the longitudinal slope is relatively gentle, basically between 1 / 7000 and 1 / 10000. On the other hand, after the replacement, the bottom of the channel is full of permeable materials, and water cannot form runoff when it enters, and can only stay in one direction.

[0007] Once water enters the channel foundation after being soaked under the geomembrane and cannot be discharged in time, the water pressure behind the membrane will be relatively large, which will cause deformation of the lining structure and may also cause deformation and damage to the channel slope of the soft rock or impermeable soil foundation after saturation.

[0008] To this end, a solution for the longitudinal and transverse drainage system of long-distance water supply channels is provided, which includes:

[0009] Longitudinal drainage arranged along the longitudinal line of the bottom of the channel, said longitudinal drainage is used to collect seepage water in the channel foundation;

[0010] and a transverse drainage, the transverse drainage being arranged along a transverse line, the water inlet of the transverse drainage being connected to the longitudinal drainage, and the slope of the transverse drainage being greater than the slope of the longitudinal drainage;

[0011] Wherein, when the conditions for gravity flow are met, the water outlet of the horizontal drainage will discharge the water to the low-lying area (fill section);

[0012] When the conditions for gravity flow are not met, the outlet of the lateral drainage is connected to a water collection well to discharge water into the water collection well; the water collection well is set in the excavation section.

[0013] In this scheme, the longitudinal drainage is a trapezoidal section with a longitudinal slope of 1 / 500, sloping towards the nearest transverse drainage.

[0014] In addition, the longitudinal drainage is filled from bottom to top with 40cm to 90cm thick medium stone filter, 20cm thick small stone filter and 20cm thick coarse sand, and a cloth and a membrane are laid in the longitudinal drainage ditch;

[0015] A PE pipe and a soft permeable pipe are also arranged in the longitudinal drainage ditch.

[0016] Furthermore, the longitudinal drainage is an inverted "V"-shaped continuous structure in the longitudinal direction. This design ensures a slope for the longitudinal drainage, while also allowing the height difference of the longitudinal drainage to remain consistent with the height difference of the longitudinal slope of the channel, thereby reducing the amount of excavation and engineering investment.

[0017] Wherein, the transverse drainage is respectively arranged at the left and right ends of the inverted "V" shape of the longitudinal drainage;

[0018] The transverse slope of the transverse drainage is 1 / 40.

[0019] Furthermore, the transverse drainage inlet is connected to the longitudinal drainage through a water collecting tank, the water of the longitudinal drainage is first discharged to the water collecting tank, and then the transverse drainage discharges the water in the water collecting tank.

[0020] In addition, the lateral drainage is composed of 2 PE pipes.

[0021] In this technical solution, a horizontal drainage is set up for one kilometer, and then a 1 / 500 longitudinal drainage is set in the middle of this kilometer, guiding the horizontal drainage from the middle to both ends. In this way, the longitudinal slope can drain water more easily. At the same time, the drainage efficiency is further increased with the help of the horizontal drainage with a slope of 1 / 40, ensuring that the seepage water can be discharged in time.

[0022] Then, if conditions permit, the seepage water will be drained away by gravity; if the terrain conditions do not permit and the water cannot be drained from the excavated channel, a collection well will be set up to pump the water into the channel.

[0023] In addition, soft permeable pipes and PE drainage pipes are added to the longitudinal drainage, adding the functions of soft permeable pipes (three-dimensional filtering structure: geotextile wrapped with high-strength spring steel wire + polyester fiber) and PE pipes (smooth inner wall, Manning coefficient n=0.009). Soft permeable pipes usually have high permeability and can collect surrounding water, while PE pipes, as rigid pipes, can provide a stable drainage path. The combination of the two may enhance drainage capacity, especially under different water level conditions: when the water level is low, soft permeable pipes can collect dispersed water flows, while PE pipes are responsible for quickly discharging large amounts of water to avoid blockage.

[0024] In addition, considering the relatively gentle longitudinal slope of the drainage (1 / 500), the drainage speed of the ditch relying solely on longitudinal drainage may not be sufficient, and adding pipes can accelerate the water flow. In particular, the transverse drainage slope is larger (1 / 40), and PE pipes are more effective here to ensure that water can be quickly discharged to the water collection well or low-lying areas.

[0025] More importantly, the soft permeable pipe has a filtering function to prevent blockage, and the PE pipe serves as the main drainage channel. The two complement each other and improve the reliability and efficiency of the overall system. In addition, if there is a high water level or a sudden increase in water volume, the pipeline system can respond more quickly to avoid the impact of accumulated water pressure on the lining structure.

[0026] In summary, the use of two types of pipes combined with the channel's filter layer is to meet drainage needs in different situations, improve the reliability and efficiency of the system, prevent blockage, and adapt to effective drainage under gentle slope conditions.

[0027] As a further improvement of the technical solution, the channels of water diversion projects and water transmission projects are all in uninhabited areas with no electricity. Therefore, solar power generation can be used in conjunction with pumping control. Specifically, a liquid level gauge is installed in the water collection well, and then pumping is started when the water level reaches the top height value. When the water level drops to the bottom height value, the power is automatically cut off and pumping is stopped through liquid level control.

[0028] As a preference, the bottom height value is flush with the bottom of the lateral drainage, and the top height value is 2-3m higher than this. When it affects the slope of the channel, I start pumping water.

[0029] As a further improvement of the technical solution, two layers of replacement filling areas are arranged at the bottom of the channel, including a gravel-containing white sandstone replacement filling area and a gravel replacement filling area;

[0030] The gravel replacement area is laid above the gravel-containing white sandstone replacement area;

[0031] The permeability coefficient of the gravel replacement area is greater than that of the gravel-containing white sandstone replacement area;

[0032] Among them, the seepage water is collected into the longitudinal drainage through the gravel replacement area, and the gravel-containing white sandstone replacement area is used to block the seepage water from entering the basic mudstone.

[0033] In addition, the channel bottom adopts a cast-in-place concrete arc lining structure, which from top to bottom includes a cast-in-place concrete slab, two cloths and one membrane, and mortar under the membrane. The arc lining structure is smoothly connected to the trapezoidal channel bottom upstream and downstream.

[0034] The channel slope of the channel adopts a precast concrete slab lining structure, which from top to bottom includes a precast concrete slab, mortar under the slab, two cloths and one membrane, and mortar under the membrane.

[0035] In this scheme, the upper gravel material forms a drainage priority layer through high permeability, actively guiding the direction of water flow; the lower gravel-containing white sandstone forms a semi-permeable buffer layer, which allows appropriate drainage while avoiding excessive seepage that damages the mudstone foundation.

[0036] The design of the lining structure should also be considered. The cast-in-place concrete curved bottom may be more solid and prevent leakage, while the prefabricated slab is convenient for slope construction, and the combination of two cloths and one membrane enhances anti-seepage. The mortar under the membrane plays a role in leveling and protection. The purpose of these layered designs on the structure is to find a balance between anti-seepage and drainage, so that water cannot penetrate into the channel foundation, and the existing seepage water can be drained away in time.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] In the longitudinal and transverse drainage system of this long-distance water transfer channel, mudstone is replaced in the entire section of the channel and a longitudinal and transverse drainage system is added to the channel bottom. Pumping and drainage are carried out throughout the year during the channel water operation period and the water outage period. The post-membrane seepage during the operation period and the pore water in the channel bed soil after the water outage are discharged from the channel bed, ensuring that the channel bed is relatively dry before winter. Therefore, no anti-frost heave design of the channel is performed, saving investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the longitudinal and transverse drainage system structure of the present invention;

[0040] Figure 2 This is a cross-sectional schematic diagram of the mudstone foundation drainage reconstruction of the present invention;

[0041] Figure 3 The second cross-sectional schematic diagram of the mudstone foundation drainage reconstruction of the present invention;

[0042] Figure 4 The third cross-sectional schematic diagram of the mudstone foundation drainage reconstruction of the present invention;

[0043] Figure 5It is a schematic diagram of the channel bottom structure of the present invention;

[0044] Figure 6 It is a schematic diagram of the connection structure of the longitudinal drainage and the transverse drainage of the present invention;

[0045] Figure 7 It is a schematic diagram of the longitudinal drainage structure of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] The mudstone channel was reconstructed according to the treatment measures of focusing on prevention and combining prevention and drainage. A longitudinal and transverse drainage system for long-distance water conveyance channels was proposed for the entire section of the mudstone channel bed. The drainage system adopts a double-layer paving type. Figure 1 As shown, longitudinal and transverse drainage is set up at the bottom of the channel to discharge the seepage water from the channel foundation outside the embankment through transverse drainage, and the transverse drainage interval is 0.5km-1.2km. After the excavation of the channel replacement section, a layer of soil with a small permeability coefficient is first laid on the mudstone foundation surface, and then a layer of gravel with a large permeability coefficient is laid on the side close to the channel lining structure. The channel seepage water will quickly gather into the drainage body at the bottom of the channel through the permeable materials on the channel slope and the bottom of the channel and be discharged. The filler with a small permeability coefficient can prevent the channel seepage water from entering the foundation mudstone.

[0048] According to the distribution of mudstone at the channel foundation and the reconstruction forms of various sections of the channel over the years, there are generally three implementation methods for replacing the entire section of the channel.

[0049] First embodiment, see Figure 2 As shown in the figure, when the mudstone foundation exposed by the excavation of channel 100 is distributed in the whole section, two layers of replacement filling materials are used for the whole section, the thickness of the channel bottom replacement filling is 2.0m, the thickness of the channel slope 110 replacement filling is 2.0m, and the excavation slope of the channel slope 110 is 1:2. The side close to the channel bed is replaced with white sandstone or gravel soil (i.e. Figure 2 The gravel-containing white sandstone replacement area) and other soil materials with low permeability coefficient are 1.5m thick, close to the lining structure (combined with Figure 5 As shown in the figure, a 0.5m thick permeable gravel layer is laid, and longitudinal drainage is laid along the bottom of the gravel layer at the bottom of the channel.

[0050] like Figure 5As shown, the channel 100 is lined with a cast-in-place concrete arc lining structure 120, which includes, from top to bottom, a 10 cm thick cast-in-place concrete slab, two cloths and one membrane (membrane thickness 0.6 mm), and 3 cm thick mortar under the membrane. The arc lining structure 120 has a radius of 8.47 m, an inscribed channel bottom width of 4 m, and is smoothly connected to the trapezoidal channel bottom upstream and downstream. The channel slope 110 adopts a precast concrete slab lining structure, which includes, from top to bottom, a 6 cm precast concrete slab, 3 cm thick mortar under the slab, two cloths and one membrane, and 3 cm thick mortar under the membrane.

[0051] Second embodiment, see Figure 3 As shown in the figure, when mudstone is distributed at the bottom of the channel, two layers of filling material are used only within 3m above the bottom of the channel. The channel slope 110 above 3m from the bottom of the channel is replaced with one material, and 0.5m thick drainage gravel with a larger permeability coefficient is used for replacement (i.e. Figure 3 In the gravel replacement area, longitudinal drainage is laid at the bottom of the gravel layer at the bottom of the channel, and a cast-in-place concrete arc channel bottom section is used.

[0052] The third embodiment, see Figure 4 As shown in the figure, the mudstone channel section that has been treated during the operation and management period and the white sandstone channel bed section with large deformation in the local section are replaced with a single material in the whole section, and cement is laid at the bottom of the channel slope replacement layer to mix the cement soil waterproof layer. The whole section is replaced with drainage gravel with a large permeability coefficient. The replacement thickness of the channel slope is 0.4m, the replacement thickness of the channel bottom is 0.5m, the cement soil mixing thickness is 0.1m, the cement content is 5%, and the lining structure is the same.

[0053] The three implementation methods mentioned above all have vertical and horizontal drainage at the bottom of the channel. Figure 5 As shown, the longitudinal drainage at the bottom of the channel is set below the original channel bottom replacement permeable gravel layer, with a trapezoidal cross-section, a bottom width of 800mm, a depth of 0.8-1.3m, a side slope of 1:0.5, a longitudinal slope of 1 / 500, and a slope to the nearest horizontal drainage. From bottom to top, the longitudinal drainage is filled with 40cm-90cm thick medium stone filter, 20cm thick small stone filter and 20cm thick coarse sand, and a cloth and a membrane are laid in the ditch. At the same time, a PE pipe and a soft permeable pipe are set in the ditch, both of which are DN160 in diameter.

[0054] See also Figure 1 and Figure 2 As shown, see especially Figure 6 and Figure 7As shown in the figure, the transverse drainage is set every 500m or so according to the length of the mudstone replacement section. The transverse drainage inlet is connected to the water collection box of the longitudinal drainage at the bottom of the channel. Two DN180 PE pipes are used for transverse drainage, and the ends are directly extended into the water collection well 200 outside the channel embankment. The water collection well 200 is set outside the channel embankment about 30m to the left of the channel 100. A prefabricated reinforced concrete pipe with a diameter of 3.0m is used, and the elevation of the bottom of the well is 3m lower than the axis of the transverse drainage pipe. For transverse drainage locations where the terrain has gravity conditions, gravity is used to discharge the seepage water from the channel foundation. Gravity transverse drainage uses buried drainage pipes to drain water into the gully outside the channel 100. Two DN180 PE pipes are laid in the gully, and the longitudinal slope of the pipe is 1 / 200. A connecting pipe of the same specification and pipe material is set every 50m for transverse drainage to prevent local blockage of a single pipe from affecting the transverse drainage function.

[0055] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. Long-distance water supply channel longitudinal and transverse drainage system, characterized by: It includes: Longitudinal drainage arranged along the longitudinal line of the bottom of the channel, said longitudinal drainage is used to collect seepage water in the channel foundation; and a transverse drainage, the transverse drainage being arranged along a transverse line, the water inlet of the transverse drainage being connected to the longitudinal drainage, and the slope of the transverse drainage being greater than the slope of the longitudinal drainage; Wherein, when the conditions for gravity flow are met, the water outlet of the horizontal drainage discharges water to a low-lying area; When the conditions for gravity flow are not met, the outlet of the horizontal drainage is connected to a water collection well to discharge the water into the water collection well.

2. The longitudinal and transverse drainage system for long-distance water conveyance channels according to claim 1 is characterized in that: The bottom of the channel is provided with two layers of replacement filling areas, including a gravel-containing white sandstone replacement filling area and a gravel replacement filling area; The gravel replacement area is laid above the gravel-containing white sandstone replacement area; The permeability coefficient of the gravel replacement area is greater than that of the gravel-containing white sandstone replacement area; Among them, the seepage water is collected into the longitudinal drainage through the gravel replacement area, and the gravel-containing white sandstone replacement area is used to block the seepage water from entering the basic mudstone.

3. The longitudinal and transverse drainage system for long-distance water conveyance channels according to claim 1, characterized in that: The channel bottom adopts a cast-in-place concrete arc lining structure, which includes a cast-in-place concrete slab, two cloths and one membrane, and mortar under the membrane from top to bottom. The arc lining structure is smoothly connected to the trapezoidal channel bottom upstream and downstream.

4. The longitudinal and transverse drainage system for long-distance water conveyance channels according to claim 3 is characterized in that: The channel slope of the channel adopts a precast concrete slab lining structure, which from top to bottom includes a precast concrete slab, mortar under the slab, two cloths and one membrane, and mortar under the membrane.

5. The longitudinal and transverse drainage system for long-distance water conveyance channels according to claim 1, characterized in that: The longitudinal drainage is of trapezoidal cross-section, with a longitudinal slope of 1 / 500, sloping towards the nearest transverse drainage.

6. The longitudinal and transverse drainage system for long-distance water conveyance channels according to claim 5, characterized in that: The vertical drainage is filled with 40cm to 90cm thick medium stone filter, 20cm thick small stone filter and 20cm thick coarse sand from bottom to top, and a cloth and a membrane are laid in the vertical drainage ditch; A PE pipe and a soft permeable pipe are also arranged in the longitudinal drainage ditch.

7. The longitudinal and transverse drainage system for long-distance water conveyance channels according to claim 5, characterized in that: The longitudinal drainage is an inverted "V"-shaped continuous structure in the longitudinal direction.

8. The longitudinal and transverse drainage system for long-distance water conveyance channels according to claim 7, characterized in that: The transverse drainage is respectively arranged at the left and right ends of the inverted "V" shape of the longitudinal drainage; The transverse slope of the transverse drainage is 1 / 40.

9. The longitudinal and transverse drainage system for long-distance water conveyance channels according to claim 8, characterized in that: The horizontal drainage inlet is connected to the longitudinal drainage through a water collecting tank.

10. The longitudinal and transverse drainage system for long-distance water conveyance channels according to claim 9, characterized in that: The horizontal drainage consists of 2 PE pipes.

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