冻融作用下污泥固化轻质土动力特性及结构演化

Dynamic and structural characteristics of sludge solidified light soil under freezing-thawing action

冻融作用会影响污泥固化轻质土动力特性和结构特性。为研究不同冻融循环次数和冻结温度下的污泥固化轻质土动力特性及结构演化,对冻融循环作用后的污泥固化轻质土进行动三轴试验和固结试验。试验结果表明:在冻融循环作用下,污泥固化轻质土动应力-应变曲线呈弱应变硬化型。污泥固化轻质土动强度和变形随着冻融次数(n)的增加和冻结温度(T)的降低而减小。经历前4次冻融作用后,对固化土变形和动强度影响较大,经历8次冻融循环后基本趋于稳定。冻融循环对土体动力特性的影响本质上是对土体结构性的影响。固化土冻融结构势(mdσn)的变化规律与动强度类似,随冻融次数的增加和冻结温度的降低而下降。冻融循环次数是影响污泥固化轻质土动力特性和结构性的主要因素,冻结温度为次要因素。

Freezing-thawing action will affect the mechanical and structural characteristics of sludge solidified light soil.In order to study the dynamic characteristics and structural evolution of sludge solidified light soil under different freezing-thawing cycles and freezing temperatures,dynamic triaxial tests and consolidation tests were carried out on the sludge solidified light soil after freezing-thawing cycles.The test results show that the dynamic stress-strain curve of light soil solidified by sludge is of weak strain hardening type under the action of freezing-thawing cycle.The dynamic strength and deformation of sludge solidified light soil decrease with the increase of freezing-thawing times(n)and the decrease of freezing temperature(T).The first four freezing-thawing cycles have a great influence on the deformation and dynamic strength of solidified soil,and the dynamic characteristics of soil tend to be stable after eight freezing-thawing cycles.The influence of freezing-thawing cycle on is essentially the influence on soil structure.The variation law of freezing-thawing structural potential(mdσn)of solidified soil is similar to that of dynamic strength,showing the decrease with the increasing freezing and thawing times and the decrease with the decreasing freezing temperature.The number of freezing-thawing cycles is the main factor affecting the dynamic characteristics and structure of sludge solidified light soil,and the freezing temperature is the secondary factor.