Stability Analysis Of Rockfill Cofferdam Slopes Under The Conditions Of Rainfall

There is no high quality filling material around the circum of project during theconstruction of Xiangjiang River’s multiple hinge cofferdam, therefore,the moisture content ofclay material mainly used for filling is almost close to saturation. The stability of the weirbody is worse than other common earth-rock cofferdams, and the body is prone to damagedby infiltration such as piping. Due to excessive moisture content of materials, it would bedifficult to obtain good results by precipitation means. That is to say, it increase the difficultyof the design and construction, and is also a new topic to cofferdam. In the entire constructionprocess of the hub, the safe operation of cofferdam involves the entire diversion project, thenavigation of Xiangjiang River, and the security and progress of the entire hub projectconstruction.. This article mainly from the following several aspects of research:1）Combined with the engineering, the technical progress of the cofferdam works discusses intext. the concrete seepage prevention measures as the technology now fast development, thekey technology of soil and water stone cofferdam in slope protection structure and the cushionlayer Settings and slope toe scour processing.2) Introduced the basic theory of saturated unsaturated seepage flow problem, listedboundary conditions of seepage differential equations, derived the continuity equation ofseepage and the finite element equation of two-dimensional unsteady unsaturated seepage.3) Introduced the influence mechanism of rainfall infiltration on the geotechnical slope,By using the finite element software based on two-dimensional homogeneous cofferdamseepage control and typical heart wall cofferdams sections model, the calculation of waterlevel change and rainfall in under the influence of seepage field pointed the changes andfeatures, and analyzed. and discussed the influence of the body parameter, penetrationcoefficient function and other factors in non-stable unsaturated seepage on slope stability.4) Introduced several improved limit equilibrium methods derived by unsaturated soilstheory. Finally, to the second stage cofferdam of Xiangjiang River hub’ left bank, used the SEEP / W finite element computer program to analysis that the seepage field was influencedunder different conditions of rainfall, water level changes. Based on the analysis of seepage,used the SLOPE / W program to calculate the stability of cofferdam slope.This paper investigated the stability analysis methods about earth-rock cofferdam underthe rainfall, provided a reference to the third stage cofferdam of Changsha hub constructionand other projects, which have a certain engineering significance.