目前堤防工程安全评价方法是定性的,而堤防工程安全影响因素繁多,其影响因素既有定量又有非定量指标,且由于各指标存在不确定性和模糊性等特点,最终导致堤防的安全评价结果具有一定的不确定与随意性。为了建立定量化的堤防工程安全评价体系,以堤基工程渗流安全评价为例,分析了堤基渗透变形的主要表现形式,确定了堤基渗透破坏险情的安全主控因素,通过专家主观经验赋值法对各主控因素进行加权赋值,采用层次分析法建立了堤基渗流的安全评价模型,并利用具体的工程实例对所建立的模型进行验证。实例计算结果与工程实际相吻合,说明利用层次分析法建立定量化的堤防工程安全评价体系具有一定的准确性与可操作性。研究成果可推广至其他堤防工程中堤基渗流变形破坏的安全评估。

At present, the safety assessment method of dyke engineering is qualitative, and there are many factors, both quantitative and non-quantitative, that affect the safety of dykes. Because of the uncertainty and fuzziness of the indicators, the final result of the safety assessment of dyke is uncertain and random. In order to establish a quantitative safety assessment system for dyke, we build a safety assessment model for seepage flow in dyke foundation using analytical hierarchy process (AHP) in which the main controlling indicators are given weight by subjective experiences of experts. The model is validated by using specific engineering examples. Consistency between calculation result and engineering practice demonstrates that the presented quantitative safety assessment model based on AHP is accurate and operable. It proves that the safety evaluation system of dyke engineering established by AHP is accurate and operable.

深部岩体多处于复杂应力场和渗流场中,研究围压和渗透压作用下黏土岩特性对高放射性废物深地质处置库的设计开挖具有重要的意义。通过塔木素黏土岩围压加卸载渗透率演化试验及不同围压和渗透压下全应力-应变渗透率试验,分析了其渗透和强度特性。综合考虑围压和渗透压对黏土岩强度的影响,引入围压强化系数和渗透压弱化系数,并结合不同强度准则在表征黏土岩强度特性中的适用性对比,提出一种考虑围压和渗透压共同作用的黏土岩强度准则。研究结果表明:塔木素深部黏土岩渗透率均处于10^-20 m²数量级,其渗透率与围压的关系在加载阶段满足指数函数关系,在卸载阶段满足幂函数关系;全应力-应变过程中,黏土岩围压强化系数大于渗透压弱化系数,共同作用时,围压对黏土岩强度的影响占主导。考虑围压和渗透压共同作用的强度准则能更好地反映塔木素黏土岩的强度特性,克服了Mohr-Coulomb和Hoek-Brown强度准则仅考虑围压变化的局限。

Deep rock mass is mostly in complex stress field and seepage field. Studying the characteristics of clay rock under confining pressure and osmotic pressure is of great significance for the design and excavation of highly radioactive waste repository. In this paper, we examined the strength and permeability of Tamusu clay via permeability evolution test under loading-unloading confining pressure and full stress-strain permeability test under different confining pressures and osmotic pressures. Having compared the applicability of different strength criteria in characterizing the strength characteristics of clay, we proposed a strength criterion for clay rock in consideration of confining pressure and osmotic pressure by introducing a strengthening coefficient of confining pressure and a weakening coefficient of osmotic pressure. Results demonstrate that the permeability of Tamusu deep clay is in the order of 10^-20 m², and the relationship between permeability and confining pressure conforms to exponential function in loading stage while power function in unloading stage. In the whole stress-strain process, the strengthening coefficient of confining pressure is greater than the weakening coefficient of osmotic pressure. When working together, confining pressure has a dominant influence on the strength of Tamusu clay. The strength criterion considering the interaction of confining pressure and osmotic pressure could better reflect the strength characteristics of the Tamusu clay rock and overcome the limits of Mohr-Coulomb and Hoek-Brown strength criterion which only consider the confining pressure variation.