Optimal Placement And Effect Evaluation Of Drainage Tunnel On The Slope Engineering

China's mountainous area accounts for more than 2/3 of the land area,is a country with very frequent geological disasters,the landslide is most frequently,and it cause very serious economic losses.So the study on the slope has a very important practical significance.In this paper,the right of Ruchen Highway 6 of the contract period K21+200~K21+357 slope as an example,based on the percolation theory,have carried on the thorough analysis on the spatial position selection of drainage tunnels and the influence of distance,depth and quantity of drainage holes on slope stability against sliding.Obtained the following research results.1)It is closely related to the permeability of the upper strata of the slope and The drainage effect of drainage tunnel.The lower the permeability of the upper strata of the slope,the worse the drainage effect is,the higher the water level of the slope is;The larger the permeability of the upper strata of the slope is,the better the drainage effect is,and the lower the water level line of the slope is.2)when the drainage tunnel in the same position in x-axis,drainage tunnel elevation higher corresponding underground waterline higher,while the drainage tunnels correspond to lower elevation of underground pipeline is also lower.The B4 and B7 conditions using Bishop method and Janbu method to get the maximum stability safety factor of slope,and the safety factor of two conditions are very close.Considering the construction difficulty and the economy,it is considered that the best choice of the drainage tunnels are located in the conditions of B4.3)The drainage effect of drainage holes is worse with the smaller the depth of drainage holes.When the drainage holes depth is less than 8m,The slope safety coefficient of the slope was calculated by Bishop method and Janbu method will increase with the increase of the depth of the drainage holes,After the drainage holes depth increased to 8m,the safety factor of slope is no longer changing.4)The drainage effect is better as the drainage hole spacing is smaller.When the distance of the drainage hole is less than 3m,the stability safety factor of the slope was calculated by Bishop method and Janbu method is almost not changed with the increase of the distance between the drainage holes.After the increase of the distance of the drainage hole to 3m,the safety factor of the slope along with the two methods can be reduced with the increase of the distance between the drainage holes.5)The underground water level line of A scheme is to be higher than B program,The drainage effect of a row of drainage holes is significantly better than that of the two row of drainage holes.But the safety factor of the slope is the same in the two schemes.So the comprehensive consideration of security and economy,the better solution is provided with a row of drainage hole in the slope.