研究目的:岩土工程与所处的地质环境之间存在着密切的依存关系和相互作用.作为地质环境中最活跃因素之一的地下水,不仅可以通过力学作用影响岩土工程稳定性,还可以通过不断改变岩土体矿物成分、结构等水-岩化学作用弱化岩土体强度和刚度参数,改变岩土体的渗透特性、渗流形态和应力状态,进而影响岩土工程长期稳定性.基于此,本文以重庆砂岩为例,开展水-岩化学作用对岩土工程长期稳定性影响及其评价方法研究.研究结论:(1)提出采用离子活度积与平衡常数比值作为岩石水化学损伤判据;(2)采用化学动力学方法建立了岩石水化学损伤动态演化数学模型,分析了水溶液酸碱度、离子种类与离子浓度对砂岩损伤演化的影响效应及规律;(3)建立了岩石M-H-C耦合本构模型;(4)建立了岩石M-H-C耦合数值模拟方法,并对某一受水-岩化学作用影响的隧道长期稳定性进行了预测评估;(5)本研究结果可为受水-岩化学作用影响的岩土工程长期稳定性评价提供参考.%Research purposes:There is a close interdependent relationship and interaction between geotechnical engineering and geological environment.As one of the most active factor in the geological environment,groundwater can not only affect the geotechnical stability by mechanical action,but also can change the mineral composition of the rock structure,weaken the rock strength and stiffness parameters,change the rock permeability characteristics,seepage and stress state,thereby affecting the long-term stability of geotechnical engineering.Therefore,taking Chongqing sandstone as an example,this paper conducts research on hydro-chemical effect on long-term stability of rock mass and its evaluation methods.Research conclusions:(1) The ratio of ionic activity product and equilibrium constant was proposed as a criterion for hydro-chemical effect damage.(2)The chemical kinetics method was used to establish the dynamic evolution mathematical model of hydro-chemical effect damage,analyze the effects and regularities of acid alkalinity,ion type and ion concentration on sandstone damage evolution.(3) A M-H-C coupling constitutive model of rock was proposed.(4)A M-H-C coupling numerical simulation method was established and the long-term stability of a tunnel affected by hydro-chemical action was evaluated.(5)The research results can provide important references for long-term stability evaluation of geotechnical engineering affected by water-rock interaction.
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