Example two
 Figure 5 It shows the steps of a construction method for draining seepage by using mining waste rock to reduce the infiltration line of the tailings dam body provided by the second embodiment of the present invention, including: Step S1: Obtain according to the geological survey report and the basic design data of the tailings dam Basic information of tailings dam;
 Wherein, the basic information of the tailings dam includes at least the initial dam crest width of the tailings pond, the direction of the central axis of the dam, the highest water level in the dam and the height of the tailings dam;
 Step S2: Use mining waste rocks in the dam to construct waste stone pillars along the dam central axis;
 Wherein, the waste rock pillars include skeletons, geotextiles and mining waste rocks arranged from the outside to the inside. The diameter of the waste rock pillars is greater than or equal to the width of the initial dam crest of the tailings pond, and the height of the waste rock pillars is not less than the highest water level in the dam. Dam crest is flush;
 Step S3: Excavate a blind ditch in the tailings deposit beach surface in the dam body parallel to the direction of the central axis of the dam, spread geotextiles inside and fill with waste rocks to form a horizontal seepage drainage blind ditch. The bottom of the stone pillars are connected;
 Step S4: Lay a longitudinal drainage pipe at the bottom of the waste rock column perpendicular to the central axis of the dam. The longitudinal drainage pipe is laid obliquely to the outside of the dam surface, and one end of the longitudinal drainage pipe at the intersection with the horizontal drainage blind ditch The perforation is used as the water inlet, and the other end of the longitudinal drainage pipe is used as the water outlet, and is connected with the drainage ditch of the tailings reservoir dam.
 In the actual construction of this embodiment, first use wire mesh or bamboo strips and other materials to make the waste stone pillar skeleton, and lay geotextile in the skeleton (the function of the geotextile is to prevent sand and water seepage), and finally fill the geotextile with mining waste rocks, This constitutes a waste stone pillar. Because the construction of waste rock pillars and tailings dam construction are carried out at the same time, the waste rock pillars are constructed in layers. The height of the tailings dam and the height of the waste rock pillars are also constructed. The tops of the two are level, but the height of the waste rock pillars is not less than The highest water level in the tailings dam.
 In order to maintain the drainage performance of the waste rock pillars and ensure the solidity of the waste rock pillars, the diameter of each waste rock pillar is generally determined by the width of the dam crest at the initial stage of the tailings pond, that is, the diameter of the waste rock pillar is equal to the width of the dam crest; however, When the width of the dam crest is too small (usually less than 2 meters), the diameter of the waste rock column can be adjusted to ensure that the particle size of the waste rock particles with a large particle size (up to 500 mm) is adjusted, and the diameter of the waste rock column can be appropriately increased , The increase does not exceed 1 meter. Because the poorly graded waste rock has good water permeability, the waste rock column in this embodiment is constructed with poorly graded waste rock. The particle size of the waste rock is less than one-half of the diameter of the waste rock column. In general, the preferred waste rock The stone size range is 10-500 mm. In order to ensure that there is sufficient drainage path between each waste stone column, the center distance between the waste stone column next to the initial dam and its adjacent waste stone column is twice the diameter of the waste stone column; the center distance between the other two adjacent waste stone columns All are equal, and the value is 2-3 times the diameter of the waste stone pillar. And when the initial width of the dam crest of the tailings pond is greater than one-third of its longitudinal length, the waste rock pillars shall be arranged in a single row at equal intervals along the central axis of the dam; when the initial width of the dam crest of the tailings pond is less than or equal to its longitudinal length 1/3 of the time, the waste stone pillars are arranged in double rows at equal intervals along both sides of the central axis of the dam.
 Among them, the horizontal drainage blind ditch is set on the tailings sedimentary beach surface in the dam body and is connected to the bottom of the waste rock pillar, and the area of the blind ditch at the junction of the horizontal drainage blind ditch and the waste rock pillar is slightly larger than the bottom surface area of the waste rock pillar. The cross-sectional shape of the horizontal drainage blind trench is an inverted trapezoid. The horizontal seepage drainage blind ditch connects the waste stone pillars to each other, further improving the drainage capacity of the waste stone pillars.
 The longitudinal drainage pipeline is laid at the bottom of each waste stone pillar and connected vertically with the horizontal drainage blind ditch. In order to discharge the liquid in the waste stone pillars and the horizontal drainage blind ditch into the drainage open ditch, the pipe at the intersection of the vertical drainage pipeline and the horizontal drainage blind ditch is perforated (that is, the pipe perforation here is set as a flower tube filter. The water pipe is used as the water inlet to facilitate the liquid in the waste stone pillars and the horizontal drainage blind ditch to flow into the vertical drainage pipeline. At the same time, in order to prevent tailings sand from entering the longitudinal drainage pipeline, the outer layer of the longitudinal drainage pipeline can also be wrapped with geotextile, which has the effect of preventing sand and water seepage. In order to facilitate the smooth flow of the liquid in the longitudinal drainage pipes into the dam drainage open ditch, all the longitudinal drainage pipes can be laid obliquely to the outside of the dam surface at a slope of 1%-3%.
 For the specific implementation details and description of each step in the foregoing method embodiment, reference may be made to the description of the corresponding part of the specific working principle of each module in the foregoing device embodiment, which will not be repeated here.
 In summary, the present invention provides a construction method for draining seepage by using mining waste rock to reduce the infiltration line of tailings dam body. It uses mining waste rock that has no economic value to make waste stone pillars combined with horizontal drainage blind ditch and longitudinal drainage. Devices such as drainage pipelines form a drainage system that can flow by itself. This kind of mining waste rock has good permeability, can increase the seepage speed of the seepage water in the tailings dam, improve the anti-liquefaction ability of the tailings dam, reduce the liquefaction area of the dam body, and has low cost, simple construction, and easy promotion. Very high commercial value; at the same time, by limiting the specifications and arrangement of waste rock pillars, not only can the drainage and consolidation of tailings be accelerated, but also the stability of the tailings pond can be improved; moreover, by using mining waste rock Pillars of waste rocks are piled up inside the dam of the tailings reservoir, which reduces the contact of waste rocks from mining with the air, reduces the discharge of acid mine wastewater, and is beneficial to environmental protection.