含薄层膏盐泥岩溶蚀－破坏演化机制及其对红层坝基岩体稳定性影响评价

Aiming at stability of dam foundation rock on red layer area under dissolving effect, the system research on this project will be done. At first, through a series of tests for mudstone containing thin layer gypsum salt, such as triaxial compression test, coupled mechanics-penetration-dissolution test of crack of mudstone containing thin layer gypsum salt, the dissolving characteristics test of mudstone containing thin layer gypsum salt under different failure degree, and coupled mechanics-penetration-dissolution test of mudstone containing thin layer gypsum salt under the whole failure process of triaxial compression, coupled dissolved-failure mechanism of mudstone containing thin layer gypsum salt can be revealed, and under different distribution condition of gypsum salt layer, such as spacing of layers and layer thickness density, the evolution law between macro-dissolution and failure characteristics can be obtained. And then, based on results of tests, and plastic mechanical model of mudstone containing thin layer gypsum salt and coupled dissolved-failure mechanism of mudstone containing thin layer gypsum salt, plastic mechanical model of mudstone containing thin layer gypsum salt under dissolving effect can be built. At last, considered the influence for permeability and failure characteristics of mudstone containing thin layer gypsum salt by dissolving effect, associated with plastic mechanical model of mudstone containing thin layer gypsum salt under dissolving effect and the evolution law between macro-dissolution and failure characteristics under different distribution condition of gypsum salt layer, the method of analysis and forecast on the stability of dam foundation rock on red layer area by dissolving effect can be acquired and applied into the actual engineering. The achieved results can provide the theoretical and technical support for design and construction and safe operation of hydraulic and hydro-power engineering in red layer area of China.

本项目以溶蚀作用下红层坝基岩体稳定性为研究目标开展系统研究，首先通过一系列试验，揭示含薄层膏盐泥岩溶蚀－破坏演化机制，建立不同膏盐层分布条件（层间距、层厚密度）下含薄层膏盐泥岩宏观溶解特性与其破坏程度之间的演化规律；继而，以试验结果和分析为基础，根据含薄层膏盐泥岩塑性力学模型，以及含薄层膏盐泥岩溶蚀－破坏演化机制，建立溶蚀作用下含薄层膏盐泥岩塑性力学模型；最后，考虑溶蚀作用对渗透性质和力学性质的影响，基于溶蚀作用下含薄层膏盐泥岩塑性力学模型，并结合不同膏盐层分布条件（层间距、层厚密度）下含薄层膏盐泥岩宏观溶解特性与其破坏程度之间的演化规律，建立溶蚀作用下红层坝基岩体稳定性分析预测方法，并进行实际工程分析。本项目的研究成果可为我国红层地区水利水电工程的设计施工以及安全运营提供理论和技术支持。

含石膏、岩盐等膏盐岩的泥岩（简称为含膏盐泥岩），是红层岩石中主要岩石类别，薄层状分布是其所含原生膏盐岩的常见分布方式，在黄河、汉江及红河等目前红层区水利水电工程建设较为集中的流域皆有分布。含膏盐泥岩在地下水作用下易软化，且其膏盐组分易发生溶蚀，易诱发坝基渗流和渗透变形等问题，对红层坝基岩体稳定性造成影响。本项目以溶蚀作用下红层坝基岩体稳定性为研究目标开展系统研究，研制了含薄层膏盐泥岩裂隙应力-渗流-溶解耦合试验装置，其适用于多物理场耦合等相关实验，可实现全过程全方位变形的高精度测量；进行了不同薄层状态下含薄层膏盐泥岩力学特性试验，获取了不同薄层厚度、层数及其位置条件下含薄层膏盐泥岩试样的变形破坏特征，建立了适合于描述其力学特性的含薄层膏盐泥岩塑性力学模型，并确定了模型参数；进行了溶蚀作用下含薄层膏盐泥岩（考虑泥岩含水量、薄层膏盐岩层厚和位置等因素）单轴压缩力学特性试验，探索了应力-溶解耦合作用下含薄层膏盐泥岩的变形破坏特征；在考虑溶蚀作用对含薄层膏盐泥岩渗透性质和力学性质影响的前提下，揭示了含薄层膏盐泥岩溶蚀－破坏演化机制；基于上述试验分析结果，以及含薄层膏盐泥岩溶蚀－破坏演化机制，构建了溶蚀作用下含薄层膏盐泥岩塑性力学模型，并初步建立了红层坝基岩体稳定性分析预测方法的基本架构。本项目的研究成果可为我国红层地区水利水电工程的设计施工以及安全运营提供理论和技术支持。