| Proposed Pulang copper mine tailings library is located in the edge of the three parallel rivers world natural heritage site. Its tectonic position is made of the mid-south of the yidun ARC of the three-river tethyan tectonic domain. The reservoir with complex geological structure, soluble rocks(carbonates) occupies more than 80% in total area. In the course of engineering investigation, karst problem as the most outstanding engineering geology problem, has attracted much attention. Strong development of karst will cause potential safety hazard on stability of the tailings foundation and tailings leakage in the future. Therefore, the research of karst development characteristics and laws, controlling factor are essential and important work, especially the control function of geological structure over karst and its impact on the construction of the tailings in the future.This article is on the basis of the field based geological and hydro-geological survey and engineering survey, and combined with geological methods, regional geological background in the research area, geological structural features, distribution characteristics of karst and karst development characteristics and rules. For dominant control factors of karst development in engineering-geological structures, we will conduct in-depth studies. Currently, we used finite element method and ANSYS computational software to start the three-dimensional numerical simulation of structure-karst in the reservoir in filling conditions. Research has shown that:The type of geological structures mainly is fold structure, fault structure and joint structure in reservoir, they control the karst development in works area. On the plane, the geological structure of the different types formed the flat determinant combination style structure that was spread to NW-SE direction; On the section, formed the hedge type structure combination style. From Yanshan advanced so far, tectonic stress field in the area has undergone the NE â†'nearly SN â†' EW â†' NNW to multiphase tectonic stress field change.There are two types of Karst within the Engineering, respectively karst soil hole (surface karst) and horizontal caves(underground karst). In niru fm of middle Triassic(T2n2 limestone area, soil cave of karst near SN-NW to the three Ribbon along the tectonicridges, fissures in the reservoir area, and its development focus, assumes the distribution of beads. Development intensity is strongest where it is in thermal fleece anticline axis, thermal fleece-Chi Chang faults(F1) and thermal fleece Anticline composite belt, F2 and F4 exit of the cross clamp. Horizontal cave is mainly along the horizontal tension joint or longitudinal tension joint.Three-dimensional numerical simulations which was achieved by finite element method and ANSYS computational software indicate that horizontal caves have some deformations and displacements in filling conditions. The reason was mainly due to the strong development of karst, caused its bedrock surface and overlaying soil are uneven, and finally causing uneven settlement of Foundation in the reservoir area. Under the effect of project, the local area has the possibility of collapse, causing leakage. In the course of construction or operation, we must fully take into account the karst geological disaster and to take the necessary preventive measures. |
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