大坝及其周围地质体中渗流与应力场耦合分析

【作者】 柴军瑞；

【导师】 仟彦卿；

【作者基本信息】 西安理工大学 ， 岩土工程， 2000， 博士

【摘要】 进行大坝及其周围地质体中渗流场与应力场耦合分析，是解决评价和预测大坝、坝基、坝肩稳定性，库岸边坡稳定性等问题的关键。本文运用岩体力学、渗流力学和结构力学相结合，理论分析与工程应用相结合，大坝与周围地质体相结合的系统研究方法，以大坝及其周围有限的地质体为研究对象，以大坝及岩体的结构类型为基础，进行裂隙渗流力学基础研究，分析大坝─地质体系统的渗流问题，同时考虑渗流对介质作用的渗透静水压力和渗透动水压力（渗流体积力或裂隙壁切向拖曳力），建立大坝─地质体系统渗流场与应力场（或温度场）耦合分析的多重裂隙网络非线性数学模型，开发求解此耦合分析模型的三维有限元程序与软件，并进行小湾水电站坝区和龙滩碾压混凝土坝渗流场与应力场耦合分析，以及龙滩碾压混凝土坝渗流场与温度场耦合分析。本文在大坝─地质体系统渗流场与应力场耦合分析的多重裂隙网络模型、渗透动水压力引起的裂隙壁切向拖曳力、渗流场与温度场耦合分析的数学模型、以及大坝─地质体系统渗流场与应力场（或温度场）耦合分析的数值方法与软件等方面作了创新性的研究。实际工程计算结果表明，考虑耦合作用时，由于裂隙（层面）隙宽的减小而使总渗流量减小，使渗流场水头分布发生变化；也使岩体（坝体）各应力分量的最大值增加10％～20％左右；当水力坡度较大时，裂隙壁切向拖曳力使剪应力明显增加；和耦合分析相比较，不考虑耦合作用得出的应力结果偏于不安全。随着渗透系数的增大，渗流场对温度场的影响更加明显，而温度场对渗流场的影响减弱；渗流由低温向高温流动时，使温度场温度普遍降低，但使渗流场水头普遍升高。更多还原

【Abstract】 It is the issue for evaluating and predicting the stability of the dam, founationand abutment to investigate the analysis of coupled seepage and stress fields in thedam and its surrounding rock mass. In this dissertation, the systematic researchmethd is utilized, in which rock mass mechanics, seepage theory and structuralmechanics are combined, theoretical anaiysis and engineering application arecombined, and the dam and its surrounding rock mass are combined. The dam and itssurrounding finite rock mass are the main research object. Based on the structure ofthe dam and rock mass, analysis of seepage through the dam and its surrounding rockmass is pefformed. With the hydrotatic seepage pressure and the hydrodynamicseepage pressure (seepage body force or hauling force applied on the fissure walls)being simultaneously considered, the multiple-level fracture network non-linearmathmatical model for coupled seepage and stress (or temperatur) fields in the damand its surrounding rock mass is proposed. The 3-D finite element program andsoftware for solving the couple model is developed. The above couple models andsoftware are applied in the hydroelectric projects such as Xiaowan and LongtanHydropower Station Project. The theories such as hauling force applied on the fissurewalls, the multiple-level fracture network model for coupled seepage and stress (ortemperature) fields, and the numerical method and softwar are newly established inthis dissertation. It can be shown from engineering computation that, by means of thecouple analysis, the total flow rate decreases and the hydraulic head distributionchanges, and the maximum values of stress components increase by 10～20%. Whenthe hydraulic gradient is sharp, the shearing stress increases obviously because of thehauling force applied on the fissure walls. Compared with the couple analysis, thestress values of single analysis is non-conservative. The higher the hydraulicconductivity the more obvious the effect of seepage on temperature, and the lessobvious the effect of tomperature on seepage. When seepage flows from where thetemperature is low to where the temperature is high, the temperature decreases and theWdraulic head increases due to the couple analysis.更多还原