Experimental study and modeling of tensile strength in unsaturated silty soil
HE Wei1，GAO You1，LI Wanshuang2，LI Ze1，ZHANG Xiayang1
(1. School of Civil and Environmental Engineering and Geography Science，Ningbo University，Ningbo，Zhejiang 315211，China；
2. China MCC20 Group Corp.，Ltd.，Shanghai 200000，China)
Abstract：Engineering geological problems，such as slope instability and cracking of roadbed fills，are closely related to the tensile strength of soil. The Brazilian splitting test was used to study the tensile strength properties of unsaturated compacted specimens and dehydrated specimen in this study. The objective was to study the evolution of the tensile strength in unsaturated compacted and dehydrated specimens across a broad range of the water content. Results show that with decreasing the water content，the tensile strength of compacted specimens initially increases and then decreases，reaching its maximum value at a critical moisture content. Conversely，the tensile strength of dehydrated specimens continues to rise and eventually approaches a stable level. The difference between these two types of specimens can be attributed to the fact that the tensile strength of compacted specimens is mainly affected by capillary suction stress generated at the bending liquid surface，whereas the tensile strength of dehydrated specimens is primarily influenced by factors such as capillary suction stress and cohesive forces. Then, microstructure images of both types of specimens obtained through electron microscopy scanning experiments were carefully analyzed and discussed. Finally，an unsaturated soil tensile strength model was established based on an effective stress formula that considers both capillary and adsorption effects. The effectiveness of this model was verified using measured data.
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2024, Vol. 43 
