膨胀土-光纤界面力学性质试验

通过室内光纤拉拔试验,分别研究不同影响因素(土体干密度、土体含水量和土体上覆压力)下膨胀土-光纤界面的力学特性。试验结果表明,各组膨胀土光纤界面的位移-拉力曲线具有相似的规律,即拉力随位移先线性增大至峰值,然后逐步降低,最后趋于稳定。基于描述光纤-膨胀土界面位移-拉力的3段式拉拔模型分析得出,在相同条件下,光纤土体界面剪切强度与土体干密度、上覆压力成正相关,与土体含水率成负相关。

Experimental study on mechanical properties of interface between expansive soil and optical fiber

A series of laboratory pullout tests on the sensing optical fiber embedded in expansive soil were performed to study the impacts of three factors on soil-fiber interfacial mechanical properties, including dry density of soil, water content and overburden pressure. It is found that the displacement-pullout force curves under different test conditions have the similar rules. The pullout force increaces linearly with the pullout displacement to the maximum value, then decreases gradually and finally tends to the residual value. The optical-soil interfacial mechanical characteristics are analyzed based on a tri-linear pullout model. The shear strength of fiber soil interface is positively correlated with soil dry density and soil overburden pressure but is negatively related to soil moisture content. The study results will provide references for the further application of fiber optic sensing to expansive soil deformation monitoring in geotechnical engineering.