Slope Horizontal Drainage Hole Layout Mode Research

Horizontal drain hole is a familiar type of drainage facility in slope drainage system. Its drainage effect has great impact on the pattern of slope seepage field. And the mode of the drain hole placing determined the its effect directly. For the purpose of searching the best mode of the drain hole placing, the author used the FEM to analyse the seepage behaviors of the drain holes what located in the slope.The author has analysed the seepage behavior of the fields in slope with the major parameter of the drain hole diameter and the length of hole. It is concluded that within the usual diameter of the hole, the size of the hole diameter has only minor influence on the field and the length of hole has more distinct influence.The author has analysed the effect of the center spacing change on the seepage field. It is concluded: the determination of the center spacing may be conducted under the permissible elevation of the exit line of seepage surface on slope surface downstream.In the end, the author has analysed the seepage field what the holes are placed two rows along the slope height. Compared with the only one rows of holes in the slope seepage field analysis, its effect is more distinct. So the mode of placing two rows of holes along the slope height is recommended.