Plugging structure for sinkhole below karst depression slag field and construction method of plugging structure

Abstract

The invention discloses a plugging structure for a sinkhole below a karst depression slag yard, belongs to the technical field of karst treatment engineering, and aims to solve the problem that karst development harms the engineering safety of the slag yard. Comprising a grouted rubble retaining wall annularly arranged on the periphery of an opening of the sinkhole, a drainage pipe penetrating through the inside and the outside is arranged in the grouted rubble retaining wall, a plurality of drainage blind ditches are arranged at the bottom of a karst depression slag yard on the outer side of the grouted rubble retaining wall and filled with blind materials, and the sinkhole is filled with large stones. The structure further comprises transition area materials covering the boulders and the drainage blind ditches. According to the method, the sinkhole is mainly used for drainage of the slag stacking body, it is guaranteed that the slag stacking body is not unstable due to the sinkhole, drainage consolidation can be achieved, and the stability of the slag stacking body is improved. The structure is convenient to construct, and the sinkhole treatment effect is good. The structure is similar to a rock-fill dam, deformation coordination of all materials is good, and durability is achieved. The structure is good in residue filtering and water draining effect, can improve the shear strength index of residue bodies, and facilitates the stability of the residue bodies.

Description

Technical Field

[0001] The present invention relates to a plugging structure for a water-drop hole under a slag yard in a karst depression and a construction method thereof, belonging to the technical field of karst treatment engineering. Background Art

[0002] Soluble rocks such as limestone and dolomite are widely distributed in regions such as Yunnan and Guizhou in China. The rock joints and fissures are developed, the water permeability is strong, and the karst development is intense, which seriously endangers the project.

[0003] The site selection of the slag yard for hydropower and water conservancy projects is restricted by site conditions or environmental protection problems related to water, and often has to be arranged in karst depressions. Water-drop holes usually develop under the depressions. Sometimes, temporary factory facilities and the like are also arranged above the slag yard. After the slag yard is filled with slag, the surrounding water will still flow into the depression. After absorbing a large amount of surface water, if the channel is blocked by the slag body, a karst lake will be formed, reducing the strength of the upper slag body and endangering the safety of the slag body. If the channel is not blocked, the karst depression will further develop into a larger karst basin.

[0004] For the treatment of the karst water-drop hole under the slag yard, concrete backfilling or stone slag backfilling is usually adopted. As can be seen from the above content, concrete backfilling will block the drainage channel, and the water channel will also fail after the pores of the stone slag are blocked by the slag body, which may form a karst lake, develop other water-drop channels or cause further karst development, ultimately endangering the safety of the upper slag body.

[0005] In view of the problem that the slag yard is arranged in a karst depression with a water-drop hole, it is very necessary to design a plugging structure that can ensure the safety of the slag body and does not block the water-drop channel, causing further karst development and endangering the safety of the slag yard and the temporary facilities above it. Summary of the Invention

[0006] The purpose of the present invention is to provide a plugging structure for a water-drop hole under a slag yard in a karst depression and a construction method thereof, so as to solve the engineering problems proposed in the above background art.

[0007] The technical solution of the present invention: A plugging structure for a water-drop hole under a slag yard in a karst depression includes a grouted stone retaining wall circumferentially arranged around the water-drop hole opening. A drain pipe penetrating inside and outside is arranged inside the grouted stone retaining wall. A plurality of drainage blind ditches are arranged at the bottom of the karst depression slag yard outside the grouted stone retaining wall. The lower end of the drainage blind ditch with a lower level extends to the grouted stone retaining wall. The drainage blind ditch is filled with large stones, and large stones are also filled in the water-drop hole. A transition zone material covering the large stones and the drainage blind ditch is also included.

[0008] In the aforementioned plugging structure for a water-drop hole under a slag yard in a karst depression, the tops of the drainage blind ditch and the grouted stone retaining wall are covered with geotextiles.

[0009] In the aforementioned plugging structure for a sinkhole under a slag yard in a karst depression, the drainage blind ditch is also filled with blind materials. The blind materials are located in the middle of the drainage blind ditch, and large boulders are arranged around them.

[0010] In the aforementioned plugging structure for a sinkhole under a slag yard in a karst depression, two layers of drain pipes, upper and lower, are arranged inside the rubble masonry retaining wall, and the blind materials are at the same height as the upper layer of drain pipes.

[0011] In the aforementioned plugging structure for a sinkhole under a slag yard in a karst depression, the foundation of the rubble masonry retaining wall extends at least 0.8 m below the ground surface.

[0012] In the aforementioned plugging structure for a sinkhole under a slag yard in a karst depression, the sizes of the large boulders filled in the sinkhole and the drainage blind ditch gradually decrease from bottom to top.

[0013] A construction method for a plugging structure for a sinkhole under a slag yard in a karst depression, the construction method includes the following steps: Step 1, fill large boulders in the sinkhole, and the large boulders should ensure continuous gradation; Step 2, build a circumferential rubble masonry retaining wall around the sinkhole. The foundation of the rubble masonry retaining wall extends below the ground surface, and two rows of drain pipes are arranged at each of the two interfaces between the drainage blind ditch and the rubble masonry retaining wall; Step 3, excavate a drainage blind ditch at the bottom of the slag yard, bury large boulders in the drainage blind ditch, and at the same time bury blind materials; Step 4, cover the top within the range of the drainage blind ditch and the rubble masonry retaining wall with geotextile, and spread transition zone materials on the geotextile; Step 5, after completing the karst pipeline treatment measures, the retaining measures for the slag pile and the water protection measures around the water still need to be completed. After completing the above treatment work, the waste slag can be discharged.

[0014] Advantages of the present invention: Compared with the prior art, the present invention mainly uses the sinkhole for draining the slag pile, ensuring that the slag pile does not become unstable due to the sinkhole, but instead can drain and consolidate to improve the structural stability of the slag pile. By adopting the plugging structure of the above scheme, the present invention has the following advantages: (1) The structure is convenient for construction and has a good treatment effect on the sinkhole.

[0015] (2) The structure is similar to a rockfill dam, with good deformation coordination among various materials and is durable.

[0016] (3) The structure has a good filter slag and drainage effect, can improve the shear strength index of the slag body, and is beneficial to the stability of the slag body. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic sectional view of the plugging structure of the present invention; Figure 2 is a detailed sectional view of the plugging structure of the present invention; Figure 3 It is a schematic plan view of the plugging structure of the present invention; Figure 4 It is a detailed diagram of the blind ditch structure of the present invention.

[0018] The markings in the figure are: 1-original ground line, 2-sinkhole, 3-mortared stone retaining wall, 4-drainage blind ditch, 5-transition zone material, 6-slag pile, 7-large stone, 8-drainage pipe, 9-blind material, 10-geotextile. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0020] Embodiment 1 of the present invention: A sinkhole blocking structure below a karst depression slag dump, comprising a mortar-laid stone retaining wall 3 circumferentially arranged around the entrance of a sinkhole 2, a drainage pipe 8 penetrating the inside and outside of the mortar-laid stone retaining wall 3 being arranged inside, a plurality of drainage blind ditches 4 being arranged at the bottom of the karst depression slag dump outside the mortar-laid stone retaining wall 3, the lower end of the drainage blind ditch 4 extending to the mortar-laid stone retaining wall 3, the drainage blind ditch 4 being filled with large stones 7, the sinkhole 2 also being filled with large stones 7, and also comprising a transition zone material 5 covering the large stones 7 and the drainage blind ditch 4.

[0021] After the construction of the blocking structure of the present invention is completed, the slag body 6 can be piled up in the karst depression slag yard. In the blocking structure of the present invention, the mortar-made stone retaining wall 3 is used to surround the sinkhole 2 in an annular direction, and is combined with the drainage pipe 8 to realize the drainage of slag. The drainage blind ditch 4 can collect the water at the bottom of the slag body 6 or the surrounding groundwater through the drainage blind ditch 4 to the front of the mortar-made stone retaining wall 3, and enter the sinkhole 2 through the drainage pipe 8 for drainage. The large stones 7 in the sinkhole 2 are mainly used to block the sinkhole 2 to prevent the upper transition zone material 5 from falling into the sinkhole 2 and blocking it. The drainage blind ditch 4 is filled with large stones 7, and the gaps between the large stones 7 facilitate the flow of water along the drainage blind ditch 4 to the mortar-made stone retaining wall 3. The transition zone material 5 is used to filter the soil and drain the slag body 6 to prevent the slag body 6 from falling into the sinkhole 2 and the drainage blind ditch 4 and blocking it.

[0022] The tops of the drainage blind ditch 4 and the mortar-laid stone retaining wall 3 are covered with a geotextile 10 , which has the function of filtering residue and draining water, thereby preventing the transition zone material 5 from seeping into the drainage blind ditch 4 and the sinkhole 2 .

[0023] The drainage blind ditch 4 is filled with blind material 9. The blind material 9 is located in the middle of the drainage blind ditch 4, and large stones 7 are filled in the drainage blind ditch 4 around it. One function of the large stones 7 is to support the blind material 9, and at the same time, it can prevent the transition zone material 5 from entering the drainage blind ditch 4. The blind material 9 is arranged along the length direction of the drainage blind ditch 4 to form a drainage channel. The purpose of setting the blind material 9 is to prevent the gaps between the large stones 7 in the drainage blind ditch 4 from being blocked by sediment in extreme cases. At this time, the water flow in the drainage blind ditch 4 cannot flow out through the gaps between the large stones 7. Since the surface of the blind material 9 is wrapped with a layer of filtering material, this filtering material can prevent sediment from entering the blind material 9, thereby avoiding the blind material 9 being blocked by sediment as well, and ensuring that the blind material 9 forms an always unobstructed drainage channel. When the drainage blind ditch 4 is blocked by sediment, the water flow inside it can still flow through the drainage channel formed by the blind material 9 to the mortar rubble retaining wall 3, and finally enter the sinkhole 2 through the drain pipe 8 and be discharged. When the water level in the drainage blind ditch 4 is relatively high, the blind material 9 can achieve rapid drainage.

[0024] There are upper and lower layers of drain pipes 8 arranged inside the mortar rubble retaining wall 3, and the blind material 9 is at the same height as the upper layer of drain pipes 8. When the water flow collected in the drainage blind ditch 4 is less, it can flow into the drainage blind ditch 4 through the lower layer of drain pipes 8. When the collected water flow is more, rapid drainage can be achieved through the upper and lower layers of drain pipes 8. Of course, part of the water flow in the drainage blind ditch 4 can also directly seep away underground. When the drainage blind ditch 4 is in an extreme working condition and all except the blind material 9 inside it is blocked by sediment, at this time, the water flow can flow out through the drainage channel formed by the blind material 9 and finally flow into the sinkhole 2 through the upper layer of drain pipes 8.

[0025] The foundation of the mortar rubble retaining wall 3 extends at least 0.8 m below the ground surface to ensure the structural stability of the mortar rubble retaining wall 3. At the same time, ensure that the bottom of the foundation of the mortar rubble retaining wall 3 is above the bottom of the excavated drainage blind ditch 4, so as to ensure that all the water flow collected in the drainage blind ditch 4 enters the sinkhole 2 through the drain pipe 8.

[0026] The sizes of the large stones 7 filled in the sinkhole 2 and the drainage blind ditch 4 gradually decrease from bottom to top. The large stones 7 should ensure continuous gradation. Larger large stones 7 are filled in the lower part. The gaps between the larger large stones 7 are larger, which is convenient for water to flow downward. Moreover, the larger large stones 7 are easy to block the lower filling. And smaller large stones 7 are filled in the upper part to prevent the transition zone material 5 from infiltrating and causing contact loss, resulting in the transition zone material 5 entering the inside of the large stones 7 and causing the collapse of the transition zone.

[0027] Embodiment 2 of the present invention: A construction method for a structure for plugging a sinkhole under a karst depression slag yard. The construction sequence of the plugging structure of the present invention is as follows: Step 1: Fill large stones 7 into the sinkhole 2. The large stones 7 should ensure continuous grading so that the upper transition zone material 5 will not undergo contact loss, resulting in the transition zone material 5 entering the interior of the large stones 7 and causing the collapse of the transition zone.

[0028] Step 2: Build a circumferential mortar rubble retaining wall 3 around the sinkhole 2. The foundation of the mortar rubble retaining wall 3 needs to penetrate 0.8 m into the ground. M7.5 mortar rubble is recommended, with a cement mortar plastered surface. The circumferential retaining wall encloses the sinkhole 2 to achieve slag filtration and drainage. At the two interfaces between the drainage blind ditch 4 and the mortar rubble retaining wall 3, two rows of A40 mm PVC drain pipes 8 are set, with an interval spacing of 150 cm x 60 cm.

[0029] Step 3: Excavate a drainage blind ditch 4 at the bottom of the slag yard. Fill large stones 7 with a diameter of 5 - 80 cm into the drainage blind ditch 4, taking into account the requirements of reverse filtration. Embed SMY200K plastic blind material 9 with a diameter of 20 cm into the drainage blind ditch 4. The water collected in the drainage blind ditch 4 and the surrounding groundwater can be discharged into the sinkhole 2 through the drain pipes 8 in Step 2.

[0030] Step 4: Cover the top within the range of the drainage blind ditch 4 and the mortar rubble retaining wall 3 with geotextile 10 of 160 g / m 2 and spread the transition zone material 5 on the geotextile 10 for slag filtration and drainage.

[0031] Step 5: After completing the karst pipeline treatment measures, it is still necessary to complete the retaining measures for the slag pile 6 and the water circulation protection measures. Only after completing the above treatment work can the waste slag be discharged.

Claims

1. A sinkhole blocking structure under a karst depression slag dump, characterized by: The invention comprises a mortar-laid stone retaining wall (3) arranged in a circumferential direction around the opening of a sinkhole (2), a drainage pipe (8) penetrating the inside and the outside of the mortar-laid stone retaining wall (3), a plurality of drainage blind ditches (4) arranged at the bottom of the karst depression slag dump outside the mortar-laid stone retaining wall (3), a lower end of the drainage blind ditch (4) extending to the mortar-laid stone retaining wall (3), the drainage blind ditch (4) filled with large stones (7), the sinkhole (2) also filled with large stones (7), and a transition zone material (5) covering the large stones (7) and the drainage blind ditch (4).

2. The sinkhole blocking structure under the karst depression slag dump according to claim 1 is characterized by: The tops of the drainage blind ditch (4) and the mortar-laid stone retaining wall (3) are covered with geotextile (10).

3. The sinkhole blocking structure under the karst depression slag dump according to claim 1 is characterized by: The drainage blind ditch (4) is also filled with blind material (9), which is located in the middle of the drainage blind ditch (4) and surrounded by large stones (7).

4. The sinkhole blocking structure under the karst depression slag dump according to claim 3 is characterized by: The mortar-laid stone retaining wall (3) is provided with upper and lower layers of drainage pipes (8), and the blind material (9) is at the same height as the drainage pipes (8) at the upper layer.

5. The sinkhole blocking structure under the karst depression slag dump according to claim 1 is characterized by: The foundation of the mortar-laid stone retaining wall (3) is at least 0.8 m below the ground.

6. The sinkhole blocking structure under the karst depression slag dump according to claim 1 is characterized by: The large stones (7) filled in the sinkhole (2) and the blind drainage ditch (4) gradually decrease in size from bottom to top.

7. A construction method for a sinkhole blocking structure below a karst depression slag dump as claimed in any one of claims 1 to 6, characterized in that: The construction method includes the following steps: Step 1: Fill the sinkhole (2) with large rocks (7), and the large rocks (7) should have a continuous gradation; Step 2: construct a circumferential masonry retaining wall (3) around the sinkhole (2), wherein the foundation of the masonry retaining wall (3) extends deep below the ground, and two rows of drainage pipes (8) are respectively arranged at the interface between the drainage blind ditch (4) and the masonry retaining wall (3); Step 3: dig a drainage blind ditch (4) at the bottom of the slag dump, bury large stones (7) in the drainage blind ditch (4), and bury blind materials (9) at the same time; Step 4: Cover the top of the drainage blind ditch (4) and the mortar-stone retaining wall (3) with a geotextile (10), and lay the transition zone material (5) on the geotextile (10); Step 5: After completing the karst pipeline treatment measures, it is still necessary to complete the blocking measures of the slag pile (6) and the surrounding water protection measures. The slag can be abandoned only after completing the above treatment work.

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