Stress-Strain Behavior of Sands Cemented by Microbially Induced Calcite Precipitation
Stress-Strain Behavior of Sands Cemented by Microbially Induced Calcite Precipitation
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DOI：
10.1061/(asce)gt.1943-5606.0001302
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发表时间：
2015-06-01
影响因子：
3.9
通讯作者：
DeJong, J. T.
中科院分区：
文献类型：
--
作者：
Montoya, B. M.;DeJong, J. T.
微生物诱导方解石沉淀法是一种新型的生物介质地基处理方法，可用于提高土体的抗剪强度和刚度。通过三轴试验研究了砂土在不排水和排水剪切作用下的抗剪强度和刚度的演变规律。胶结程度从年轻的未胶结砂到高度胶结的砂岩状条件的MICP处理砂受到不排水剪切。应变硬化的应变软化行为的过渡和相应的过渡的整体局部破坏的胶结增加。适度胶结的试样经受各种应力路径，这导致剪切强度和体积行为的变化。剪切波速度被用来非破坏性地监测在剪切过程中的小应变刚度的变化，这提供了一个指示的胶结退化作为应变水平的函数。由于剪切波速度受胶结程度和剪切过程中有效平均应力变化的影响，因此使用归一化剪切模量来评估剪切过程中胶结的退化。(C)2015年美国土木工程师协会。
Microbial induced calcite precipitation (MICP) is a novel biomediated ground improvement method that can be used to increase the shear strength and stiffness of soil. The evolution of the shear strength and stiffness of sand subjected to undrained and drained shearing is evaluated using triaxial tests. MICP treated sands with cementation levels ranging from young, uncemented sand to a highly cemented sandstonelike condition are subjected to undrained shear. A transition from strain hardening to strain softening behavior and a corresponding transition of global to localized failure as cementation is increased is observed. Moderately cemented specimens are subjected to various stress paths, which result in a change to the shear strength and volumetric behavior. Shear wave velocity is used to nondestructively monitor the change in small-strain stiffness during shearing, which provides an indication of cementation degradation as a function of strain level. Because shear wave velocity is influenced by both the level of cementation and the change in effective mean stress during shearing, the normalized shear modulus is used to evaluate the degradation of cementation during shearing. (C) 2015 American Society of Civil Engineers.