Variation of Critical Water Pressure for Hydraulic Fracturing in Cement Mortar under Sulfate Attack |
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Authors: | Detan Liu Hongwei Zhang Zhenzhong Shen Liqun Xu Qiong Wu Yidong Ge |
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Institution: | 1.College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China; (D.L.); (Z.S.);2.Datang Hydropower Science & Technology Research Institute Co., Ltd., Nanning 530007, China;3.Shandong Survey and Design Institute of Water Conservancy Co., Ltd., Jinan 250013, China;4.Huaian Water Conservancy Survey and Design Research Institute Co., Ltd., Huaian 223010, China; |
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Abstract: | Hydraulic fracturing may be induced easily in a cement-based structure in a sulfate-rich environment, which threatens engineering safety. In order to investigate the evolution of critical water pressure, a series of hydraulic fracturing tests and splitting tensile strength tests on the cement mortar under different sulfate-exposure periods are performed. The critical water pressure of the cement mortar under sulfate attack experiences an initial increase stage and a subsequent decrease stage. A stress intensity factor is modified by two proposed damage variables which are crack length and fracture stress. Then, the relationship between the critical water pressure and the tensile strength is established. Moreover, an evolution model of the critical water pressure is proposed, which reveals that the matrix tensile strength and porosity of cement mortar strongly affect the critical water pressure evolution. Additionally, an empirical formula is suggested to describe the critical water pressure evolution of the cement mortar under sulfate attack, and its validity is verified by experimental results. |
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Keywords: | cement mortar critical water pressure hydraulic fracturing sulfate attack evolution model |
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