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| 红砂岩冻融循环三轴力学特性及损伤机制 |
| Triaxial mechanical properties and damage mechanism of the freeze-thaw cycle of red sandstone |
| Received:November 08, 2022 Revised:December 07, 2022 |
| DOI：10.7520/1001-4888-22-280 |
| 中文关键词: 冻融循环 红砂岩 宏观裂纹 变形特性 冻胀力 微观结构 |
| 英文关键词:freeze-thaw cycle red sandstone macroscopic cracks deformation characteristics frost heave force microstructure |
| 基金项目:国家自然科学基金项目(42077231) |
| Author Name | Affiliation | | YE Yongpeng | School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China | | YANG Shengqi* | 1.School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China； 2.China State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China | | SUN Bowen | China State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China |
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| 中文摘要: |
| 岩石的冻融破坏是寒区工程中不可忽视的自然灾害之一。为了探究冻融循环对岩石物理力学特性的影响，通过开展不同冻融循环次数下红砂岩的常规三轴试验，分析了其物理力学参数随冻融循环次数及围压的演化规律。结果表明，在冻融循环达到5次时，岩样中部表面会出现宏观裂纹且中部直径显著增大，随着表观裂纹不断发育，岩样尺寸随之增大；在单轴情况下，随着冻融循环次数的增加，单轴抗压强度不断降低，降幅最快发生在冻融循环前5次，超过2次后，岩样由脆性破坏转换为延性破坏；在三轴情况下，岩样峰值强度随冻融循环次数增加而降低，降幅最大发生在冻融循环5次以后，在冻融循环次前10次时围压对弹性模量影响较大，超过10次后冻融损伤对弹性模量影响较大。通过微观结构观察到冻融循环一方面会降低岩石矿物颗粒之间的连结紧密程度，使岩石孔隙直径增大，另一方面会使岩石颗粒崩解，破坏岩石颗粒的完整性。 |
| 英文摘要: |
| Freeze-thaw destruction of rocks is one of the natural disasters that cannot be ignored in the cold zone project. In this paper, the influence of freeze-thaw cycles on the physical and mechanical properties of petrophy was explored, and conventional triaxial tests of red sandstone under different freeze-thaw cycles were carried out, and the evolution of physical and mechanical parameters with the number of freeze-thaw cycles and confining pressure was analyzed. The results show that macroscopic cracks and the middle diameter of the rock sample increase significantly when the freeze-thaw cycle reaches 5 times, and the size of the rock sample increases accordingly with the development of apparent cracks. In the uniaxial case, the uniaxial compressive strength decreases with the increase of the number of cycles, and the fastest decline occurs in the first 5 times, and after more than 2 times, the rock sample is converted from brittle failure to ductile failure. In the triaxial case, the peak strength of rock samples decreases with the increase of the number of freeze-thaw cycles, and the largest decrease occurs after 5 freeze-thaw cycles, and the confining pressure has a greater effect on the elastic modulus 10 times before the freeze-thaw cycle, and the freeze-thaw damage has a greater effect on the elastic modulus after more than 10 cycles. The freeze-thaw cycle observed through the microstructure will reduce the tightness of the connection between rock mineral particles, increase the diameter of rock pores, and on the other hand, disintegrate rock particles and destroy the integrity of rock particles. |
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