Study Of Impact On The Ecological Effect By Karst Tunnel

Karst is not only invaluableners resource but also essential factor of environment, it is difficult to avoid Karst water during the railway-tunnel construction.It is a problem of resource as well as a environmental problem which brings about surround ground water or underground water drying, and moreleads vegetation to regress, or brings about ground's collapse, etc. ecological environment is vulnerable in Karst.Ecological environment are dramatically depending on groundwater.However little emphasis has been placed on supergene ecological environment excited by groundwater and thus, the eco-value of groundwater has not embodied during conventional evaluation , development and exploitation of groundwater resources, which not only bring about a series of negative effects to ecological environment but also severely confine society and economy development and human living space in the area.During tunnel construction, the ground water of ecological environment might be changed,Based on the ecological effect excited by groundwater of home and abroad, according to the characteristics of the impact on the ecollgical effect by tunnel karst , searches the reasons of the negative impact which the tunnel karst may do to the ecological environment, and presents the research on the principles of the comprehensive evaluation establishment about the impact on the ecollgical effect by tunnel karst. At the same time, the factors that affect the supergene eco-environment are discussed, and the hierarchical evaluation index system, the evaluation standard and the evaluation method on ecological effect excited by groundwater are formed.Finally to present the very appropriate evaluation indexes.FAHP (Fuzzy Analytic Hierarchy Process) is presented to evaluate the impact on the ecollgical effect by tunnel karst. To establish the hierarchy model of the comprehensive evaluation system, and to present the evaluation indexes of every class. Under constructing the judging matrix and calculating every index's weight, the functions have been built for the degree of subordination of the bottom indexes, and the evaluation thresholds. Having the indexes none-dimensionally, educing the degree of subordination of every index, geting the result of the comprehensive evaluation.The thesis takes Geleshan tunnel of Yuhuai Railway as an example, to analyze the impact on the ecollgical effect by tunnel karst. The impact is studied by the route of collecting materials, making an on-the-spot surveying and monitoring, analyzing data together, and every evaluation indexe is analyzed.