堆石坝面防渗土工膜顶破刺破的随机特性与概率模型研究

Nowdays there is no quantitative design method to consider the probability of geomembrane puncture on rockfill dam surface due to the random contact state between geomembrane and its cushion particles and it has hindered the development of geomembrane application in the construction of rockfill dam. In this program, the simulation test of geomembrane contact with cushion particles combined with theoretical probability analysis are employed to investigate the randomness of contact state between geomembrane and its cushion particles and a probability.model of geomembrane puncture from granular cushion on rockfill dam surface is also developed. Firstly, by designing an applicable test method the contact state can be fully measured and its statistical feature is obtained. Secondly, geomembrane puncture can be evaluated by the puncture limit test of geomembrane and the main feature of geomembrane contact state with different kind of particles at the limit state of puncture is also obtained. Finally, the mathematical model of.geomembrane puncture can be established by test data verification and correction which also gives the probability model of geomembrane puncture.

目前对于堆石坝面防渗土工膜顶破刺破问题，由于不能很好考虑膜下垫层颗粒性状的随机性，所以尚无一种科学合理的数学模型来定量描述垫层颗粒性状与土工膜顶破刺破可能性之间的关系，阻碍了土工膜这种性能优良的新型防渗材料的推广应用。本课题拟采用室内模拟试验结合随机概率理论的数学建模分析对堆石坝面土工膜与垫层颗粒随机接触状态进行系统研究，提出一种堆石坝面垫层颗粒上土工膜顶破刺破的随机概率模型。首先，通过设计切实可行的接触状态量测量方法，对试验中土工膜与垫层颗粒之间各接触状态量进行观测和记录，确定其统计分布特征和规律。其次，选择工程实际和模拟试验中典型顶破刺破现象所对应的几组不同粒径和尖锐程度的颗粒及颗粒间隙进行土工膜顶破刺破的极限状态试验，获得对应条件下土工膜顶破刺破的各极限状态量。最后，以顶破刺破极限状态量在接触状态量的统计分布中所占的比例为基础，建立堆石坝面土工膜顶破刺破的概率模型。

目前对于堆石坝面防渗土工膜顶破刺破问题，由于膜下垫层颗粒性状的随机性，所以尚无一种科学合理的数学模型来定量描述土工膜顶破刺破的可能性，阻碍了土工膜这种性能优良的新型防渗材料的推广应用。本课题拟采用室内模拟试验结合随机概率理论的数学建模分析对堆石坝面土工膜与垫层颗粒随机接触状态进行系统研究，提出一种堆石坝面垫层颗粒上土工膜顶破刺破的随机概率模型。首先，通过设计切实可行的接触状态量测量方法，对试验中土工膜与垫层颗粒之间各接触状态量进行观测和记录，确定其统计分布特征和规律。其次，根据土工膜在颗粒垫层上的最大应变量及其统计分布规律分析其在工作水压力下小于土工膜允许应变量的比例为基础，建立堆石坝面土工膜顶破刺破的概率模型。