Soil Treatment with Thixotropic Fluids: An Autoadaptive Design for Liquefaction Prevention

地震液化是引起土木基础设施破坏的一个重要原因。 它最有可能发生在细砂至中砂或更细的非塑性土壤中。 土壤中塑性细粒百分比的增加降低了循环荷载过程中土壤颗粒重排的可能性，并降低了液化的可能性。 用膨润土处理土壤可增加塑性细粒的百分比，抑制土壤颗粒的运动，从而降低土壤液化的可能性。 因此，处理过的土壤表现为被动自适应材料，当意外和潜在的灾难性事件发生时，其特性最有用。 本课题主要研究了以下几个方面的问题：（1）膨润土的加入对净砂液化势的影响。(2)土壤特性的相应变化，如刚度、强度和水力传导性。(3)一种以时间释放方式将膨润土悬浮液输送到土壤孔隙中的新方法，其中膨润土在输送后水合。

Liquefaction is an important cause of damage to civil infrastructures during earthquakes. It is most likely to occur in fine to medium sands or even finer non-plastic soils. An increase of the percentage of plastic fines within the soil decreases the likelihood of rearrangement of soil particles during cyclic loading and reduces the potential for liquefaction. Treatment of a soil with bentonite increases the percentage of plastic fines, restrains the movements of the soil grains, and thus reduces the potential for liquefaction of the soil. As a result, the treated soil performs as a passive autoadaptive material where its properties are most useful when an unexpected and potentially catastrophic event occurs. In this project the following issues are investigated: (1) Changes in liquefaction potential of clean sands as a result of the addition of bentonite. (2) Corresponding changes in characteristic soil properties such as stiffness, strength, and hydraulic conductivity. (3) A novel means by which to deliver bentonite suspensions to the soil pores in time-release fashion in which the bentonite hydrates after it has been delivered.