心墙胶结砾质土力学性能及耐久性试验研究

如何有效改善心墙拱效应是高心墙堆石坝建设中亟需解决的重要问题。通常采用砾质土以提高心墙的变形模量，但对于300 m级高坝，砾质土心墙拱效应仍较为明显，而更多掺砾，可能会导致心墙防渗性能下降。本文研究常见的三种固化剂掺加下胶结砾质土作为高心墙坝料的可行性，分析了固化剂类型和掺量对胶结砾质土力学性能和耐久性能的影响，利用扫描电镜分析了不同胶结砾质土性能差异的原因。试验结果表明，HAS?胶结砾质土表现出了更高的抗压抗拉强度、更大的变形模量和更好的韧性，且抗渗性和抗冻性最优，致密性高。故将HAS胶结砾质土作为高心墙坝料，可在不增加掺砾的情况下提高心墙的变形模量，有助于降低心墙拱效应，为超高心墙堆石坝心墙坝料选择提供一种新的可能。

Experimental study on mechanics and durability of cemented gravel-mixed soil of core wall

How to reduce the arch effect of a soil core wall effectively has become an important issue for high rock-fill dams. A common solution is to mix a certain amount of gravel into the clay soil of the core wall to increase its deformation modulus. However, the arch effect of such core walls is still significant for 300 m high dams. If more gravel is mixed, the modulus would undoubtedly be improved, but its impermeability may inevitably be weakened. This paper evaluates the feasibility of a new core wall material for high earth-rock dams–a cemented gravel-mixed soil mixed with three different soil solidifiers, examines the effects of solidifier type and content on its mechanics and durability, and demonstrates the causes of differences in its performance of different types through scanning electron microscope tests. We found the HAS type has the advantages of higher compressive and tensile strengths, larger deformation modulus and toughness, and better impermeability, frost resistance and compactness. Thus, the mixed soil of this type increases the deformation modulus of core walls without increasing the amount of gravel, helping reduce the arch effect of core walls and providing a new alternative for core wall improvement.