动荷载下砂土与EPS颗粒混合的轻质土变形特性的试验研究

Test study on deformation characteristics of lightweight sand-EPS beads soil under dynamic load

砂土与EPS颗粒混合的轻质土(LSES)是一种通过减轻地基压力、提高地基承载力以处理不良地基的新型轻质土工材料。由于LSES主要用作路基填土,因此,其在动荷载下的变形特性值得关注。基于室内动三轴试验结果,讨论了围压、水泥掺量、EPS含量以及循环加载次数对LSES动变形特性的影响。当围压较低时,LSES会呈现出与EPS块体相似的线性动应力-应变关系;而在较高围压下,LSES的动应力-应变拟合曲线则为双曲线型。在给定的应变水平下,LSES的割线动弹性模量Esec随着围压和水泥掺量的增加而增加,随循环加载次数的增多而逐渐衰减,EPS含量增多时,Esec-εd曲线更趋于平缓。

Lightweight sand-EPS beads soil（LSES） is a novel lightweight geomaterial to improve soft ground by reducing vertical pressure on ground and improving the bearing capacity of ground.Because LSES is mainly used as subsoil,its deformation characteristics under dynamic load is worth to study.Based on laboratory cyclic triaxial test data,the effects of confining pressure,cement content,EPS content and number of loading cycles on the dynamic deformation characteristics of LSES are discussed.Under low confining pressure（σc=50 kPa）,LSES shows linear dynamic stress-strain relationship similar with that of EPS block;while under relatively high confining pressure（σc=100,150 kPa）,its fitting dynamic stress-strain curve is hyperbolic type.Under given strain,the dynamic secant elastic modulus（Esec） of LSES increases with increasing confining pressure and cement content while decreases with increasing number of loading cycles;and Esec- εd curve is more smooth when EPS content increases.