拦河闸闸基构造稳定性分析评价

Analysis and evaluation of tectonic stability of dam foundation

通过对区域地质构造及基本地震烈度、闸基地层结构特征、闸基水文地质特征、闸基岩土物理力学特征、闸基稳定性以及闸基渗透稳定性的分析,对渭河宝鸡市区段拦河闸工程的闸基构造稳定性进行分析评价,得到如下结论:①闸基地层由新第三系粘土与砂砾岩互层和第四系冲击粉土与砂砾岩组成,且地形平坦,不存在滑坡、泥石流以及振动液化等不良地质现象。②闸基地下水为浅层孔隙性潜水和承压水,均对普通水泥无腐蚀性。河水水质虽受污染,但对于抗硫酸盐水泥无腐蚀性。③闸基位于冲击砂卵砾石之中,该层厚度较大且较为稳定,密实程度为中密—密实,骨架作用较强,含粘土,局部呈微胶结及半胶结,具有低压缩性、力学强度高、稳定性好等特性,满足闸基负荷要求,闸基范围内无承压含水层,闸基抗滑稳定性较好。④闸基底面渗透比降略小于允许水力坡降,不会发生管涌或流土,但应结合防渗要求适当进行处理。

Based on detailed data,structural stability of dam foundation was analyzed by studying the region geological conformation,seismic intensity,and structure characters of strata,hydrogeological situation,physico-mechanical parameters of strata and osmosis stability.Some conclusions are drawn as follows:1.Strata of dam foundation are made up of red clay and a sandy pebblestone layer in the Pliocene series(N_2)and alluvial sandy pebblestone as well as a powder soil layer in the Holocene series(Q_4). It was smoothness and inexistence of landslide,debris flow and liquescence.2.Groundwater in the project area can be divided into porosity underwater of loose superficial layer in the Quaternary and artesian water from the deep sandy gravel rock layer in the Neogene,and both of them do not bear causticity to the common concrete.Surface water does not bear causticity to the resisting-sulfate concrete,though it has been polluted.3.Dam foundation is located at alluvial sandy pebblestone,which is so thick, steady and close-grained that it possesses enough ability to support the dam foundation.Furthermore,no artesian aquifers are in the range of the dam base and the dam groundwork bears nice stability against sliding.④Hydraulic slope is less than the permissible hydraulic slope.Therefore,the dam foundation and the sandy gravel layer in the protective-apron base will not result in a piling effect.