Experimental and Numerical Investigation of Mechanical Behaviors of Cemented Soil–Rock Mixture

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• 作者：Lei Jin ; Yawu Zeng ; Lei Xia ; Yang Ye
• 关键词：Cemented soil–rock mixture ; Large ; scale triaxial tests ; Rock block proportion ; Irregularly shaped rock blocks ; Discrete element modeling ; Mesoscopic mechanism
• 刊名：Geotechnical and Geological Engineering
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：35
• 期：1
• 页码：337-354
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Geotechnical Engineering & Applied Earth Sciences; Hydrogeology; Terrestrial Pollution; Waste Management/Waste Technology; Civil Engineering;
• 出版者：Springer International Publishing
• ISSN：1573-1529
• 卷排序：35

文摘

In order to reveal the macroscopic mechanical properties and mesoscopic failure mechanism of cemented soil–rock mixture (CSRM, for short) that widely exists in nature, a series of large-scale triaxial tests are carried out. Firstly, specimens of soil–rock mixture without cement and specimens mixed with small amounts of cement are compared to demonstrate that it is necessary to further divide soil–rock mixture into CSRM and uncemented soil–rock mixture. Then, laboratory large-scale triaxial tests on CSRM specimens with different rock block proportion (RBP, for short) are conducted to explore the effect of RBP on the macroscopic mechanical responses of CSRM. Finally, based on the developed three-dimensional discrete element modeling technology for irregularly shaped rock blocks and soil–rock mixture, a numerical simulation of laboratory tests is performed to analyze the mesoscopic failure mechanism of CSRM. The results indicate that CSRM specimen with 3 % cement exhibits strain softening and localization, whose strength and modulus increase dramatically compared with those of specimen without cement. Peak strength and brittleness index of CSRM specimen both are decreased with increasing RBP under the confining pressures of 0.1, 0.2 and 0.3 MPa. In CSRM specimens, microcracks initiate at the soil–rock interfaces, and then propagate in soil matrix bypassing the rock blocks with multiple tortuous failure bands coming into being throughout the specimen eventually. The effect of RBP on strength of CSRM depends on the combination of skeleton-effect of rock blocks and cementation-effect of the specimen.