Three Dimensional Seepage Characteristic Analysis About Earth-Rock Dam Of Deep Overburden Layer

Deep overburden layer refers to quaternary period loose deposits whose thickness is more than 30m accumulated among the valley. It has some characteristics of structure looseness, lithology discontinuance, great changes in horizontal and vertical, complex genetic type, more uneven in physical and mechanical properties. With the development of water conservancy, most earth-rock dam built in southwest china will encounter deep overburden layer foundation. Seepage control technique and seepage stability of deep overburden layer earth-rock dam have become the prominent problems.In this paper, the author has researched deeply on the principles and measures of seepage control by taking a hydro dam in Tibet as the object of study and combining previous research results; has analyzed seepage field, seepage flow, seepage gradient of the dam area program under diffderent seepage control based on software ADINA and Geostudio of finite element theory; and has recommended optimization program and analyzed intuitively three-dimensional permeability of deep overburden layer earth-rock dam. Here are the following studies of the paper:1). According to the principles of seepage control, the paper systematically expounded the measures of deep overburden layer foundation seepage control, connecting type of seepage system, and the effect of the practical application in engineering; provided references for deep overburden layer basic seepage control of a hydro dam in Tibet.2). According to the basic characteristics and distribution characteristics of a hydro dam cover in Tibet, the paper evaluated Permeability and Seepage stability, and established evaluation criteria of seepage.3). Based on the finite element methods software, the paper analyzed seepage field, seepage flow, seepage gradient in this dam, and studied on the effect of seepage in different seepage design4). According to the different effect of seepage, the paper recommended the best plan of seepage control, and proposed the stressed aspects of study in the next stage, and gave the guidance suggestion for the improvement of seepage control.