Analysis on Blocking Impact of Right Platform of Xin'an River Dam Based on Saturated-Unsaturated Theory

Considering the heavy rain conditions, the saturated - unsaturated flow field of Xin'an river dam’s right bank after blocking is analyzed and foundation’s uplift pressure of he right shoulder of the dam and variation of rock’s water table are studied here to evaluate the practical effect of blocking the platform based on three-dimensional saturated-unsaturated seepage theory and its anti-analysis theory. The calculation and analysis results show that after the platform blocked, it effectively blocked surface infiltration of rainfall in this area and reduced the lateral supply from rainfall infiltration to the around rock and as well as improved the movement state of groundwater at right abutment slope which to a certain extent helped to reduce the dam foundation’s uplift pressure. Therefore the conclusion can be drawn that the blocking of the platform has a positive effect on the dam’s safety. Cable machine system was used to constructing xin’an river dam and platform for cable machine were excavating at 142m and 175m in the mountain which caused bedrock bare while no covering treatments were taken after the construction. These made the rainfall infiltration easily and thus increased the lateral recharge to adjacent dam’s groundwater. Conclusion that there existed a seepage channel around the dam near the right shoulder was made when first dam safety periodic inspection. Therefore，the blocking and drain engineering of the 142m platform were first taken to reduce the directly supply from the rain that fell down on the platform to the right shoulder’s seepage flood. Then 175m platform on the right shoulder was covered with concrete blocking and drainage treatments were also applied to block the surface water infiltration in the area and further to reduce the right shoulder’s water