覆盖层上胶凝砂砾石坝应力应变特征及影响因素

为了研究在覆盖层上的胶凝砂砾石坝的应力应变特征及影响因素,为未来在覆盖层上建造胶凝砂砾石坝做准备,使用三维有限元模拟,基于一种考虑了围压的修正邓肯—张模型模拟胶凝砂砾石料,对正常工况下的覆盖层上的胶凝砂砾石坝进行了模拟,并分别考虑了覆盖层厚度、弹性模量以及坝体胶凝材料掺量对覆盖层上胶凝砂砾石坝坝体内部的应力应变的影响。结果表明:覆盖层厚度、弹性模量以及坝体胶凝材料掺量与坝体位移呈现明显的线性关系,坝体位移随着覆盖层厚度的增加与弹性模量的降低而增大,但对坝体大、小主应力的影响不明显。即使在较软、较厚的覆盖层上,胶凝砂砾石坝仍然可以承受较大的变形而坝体内部应力变化不剧烈。该研究成果可以为胶凝砂砾石坝的选址提供一定的参考作用,可拓宽胶凝砂砾石坝的选址范围。

Stressstrain characteristics and influencing factors of cemented sand and gravel ( CSG) dam upon overburden

In order to study the stressstrain characteristics and influence factors of cemented sand and gravel ( CSG) dam upon overburden for preparing the construction of CSG dam upon overburden in the days to come， the CSG dam upon overburden under normal working condition is simulated with 3 － D finite element simulation on the basis of a CSG material simulated by modified Duncan-Chang model with the consideration of confining pressure; in which the influences from the thickness and elastic modulus of overburden and the cement mixing proportion of dam body on the stressstrain inside the body of CSG dam upon overburden are respectively considered. The result shows that the thickness and elastic modulus of overburden and the cement mixing proportion of dam body exhibit obvious linear relationships with the displacement of dam body，while the displacement of dam body increases along with the increase of the thickness of overburden and the decrease of the elastic modulus，but no significant influences are there on both the maximum and the minimum principal stresses of the dam body. Even if upon the softer and thicker overburden，CSG dam can still bear larger deformation without dramatical changeof the stress inside the dam body. The study result can provide a certain reference for the site selection for the construction of CSG dam and enlarge the range of the site selection as well.