李家河水库坝基(肩)工程地质问题与处理

The Engineering Geological Problems and Treatment on the Foundation(Abutment) of Lijiahe Reservoir Dam

西安市辋川河引水李家河工程近期建成竣工并已开始蓄水。拦河大坝为碾压砼抛物线双曲拱坝,最大坝高98.5 m,坝体厚高比0.315,是一座薄碾压砼高拱坝。设计建基要求865 m高程以下微风化—新鲜Ⅱ类岩体,865 m高程以上微—弱风化的中下部Ⅱ-Ⅲ类岩体。相应要求弹性波速分别>4 000 m/s和3 600 m/s。坝址地形为中低山峡谷区,河谷"V"字型发育,较窄。坝基岩性为燕山期侵入花岗岩,构造不发育,岩体坚硬,完整性好。但坝基岩体受风化、构造影响,局部存在不良工程地质问题和地质缺陷,不满足设计建基要求。通过对建基面岩体的工程地质条件分析论证,提出对不满足建基要求的岩体进行挖除换填、锚固、灌浆等工程处理措施,处理后达到建基岩体要求。

Lijiahe reservoir dam in Xi＇an Wangchuan river which designed by Shannxi institute of water resources and e-lectric power investigation and design was completed and started to store water .The dam is a parabola hyperbolic arch dam with 98.5m height and 0.315 thickness ratio.The foundation should be on the rock which had the breeze to freshⅡquality following the 865m,and which had the breeze to weak weathering above the 865m,and correspond to which ,the elastic wave velocity should be more than 4 000 m/s and 3600m/s.The terrain is low mountain and canyon which was＂V＂ type and narrow .The dam bedrock of Yanshan period is the intrusive granite ,the structure is not developed ,the rock mass is hard and the integrity is good .However with the excavation of dam foundation rock under influence of weathering and tectonic ,local existence of poor engineering geological problem and geological defects , which can not meet the re-quirements of foundation .Through the analysis on the engineering geological condition of the dam foundation , measures such as filling ,anchoring ,and grouting on the rock which was not meet the requirements of foundation is proposed in or -der to meet the the foundation requirement .