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马冬冬, 汪鑫鹏, 张文璞, 马芹永, 周志伟, 张蓉蓉. 冲击荷载作用下冻土劈裂拉伸破坏特性试验研究[J]. 岩土工程学报, 2023, 45(7): 1533-1539. DOI: 10.11779/CJGE20220981
引用本文: 马冬冬, 汪鑫鹏, 张文璞, 马芹永, 周志伟, 张蓉蓉. 冲击荷载作用下冻土劈裂拉伸破坏特性试验研究[J]. 岩土工程学报, 2023, 45(7): 1533-1539. DOI: 10.11779/CJGE20220981
MA Dongdong, WANG Xinpeng, ZHANG Wenpu, MA Qinyong, ZHOU Zhiwei, ZHANG Rongrong. Experimental study on splitting tensile failure characteristics of frozen soils under impact loads[J]. Chinese Journal of Geotechnical Engineering, 2023, 45(7): 1533-1539. DOI: 10.11779/CJGE20220981
Citation: MA Dongdong, WANG Xinpeng, ZHANG Wenpu, MA Qinyong, ZHOU Zhiwei, ZHANG Rongrong. Experimental study on splitting tensile failure characteristics of frozen soils under impact loads[J]. Chinese Journal of Geotechnical Engineering, 2023, 45(7): 1533-1539. DOI: 10.11779/CJGE20220981

冲击荷载作用下冻土劈裂拉伸破坏特性试验研究

Experimental study on splitting tensile failure characteristics of frozen soils under impact loads

  • 摘要: 冻土的动态拉伸强度和破坏特性在涉及冻土工程高效破碎和安全稳定性分析领域具有重要的参考价值。为研究负温和加载率对冻土动态拉伸性能的影响,利用铝质分离式Hopkinson压杆试验系统开展了冻土的动态巴西圆盘劈裂试验,结合高速摄像系统,分析了温度和加载率对冻土动态拉伸强度、能量耗散和破坏模式的影响,探讨了冻土巴西圆盘的劈裂破坏机理及动态拉伸强度的影响因素。结果表明:冲击荷载作用下,冻结黏土和冻结砂土巴西圆盘试样均遵循中心起裂的破坏模式,试件破坏为沿轴向相对完整的两半;随着冲击气压的增加,两种冻土的加载率均呈线性增大;两种冻土达到动态拉伸峰值应力所需的时间在92~242 μs范围内;两种冻土的动态拉伸强度均存在明显的温度效应和加载率效应,动态拉伸强度随温度的降低和加载率的增加而增大;不同负温条件下两种冻土的吸收能与动态拉伸强度均存在较好的线性关系;冲击气压的增加会导致冻土试样的破坏程度加剧,高剪切应力引起的三角破碎区面积逐渐增大。

     

    Abstract: The dynamic tensile strength and failure characteristics of frozen soils have important reference value in the field of efficient crushing and safety stability analysis of frozen soil projects. To study the effects of negative temperature and loading rate on the dynamic tensile properties of the frozen soils, the aluminum split Hopkinson pressure bar system is employed to conduct the dynamic Brazilian disc splitting test of frozen soil. In addition, by using the high-speed camera system, the influences of temperature and loading rate on the dynamic tensile strength, energy dissipation and failure mode of the frozen soils are analyzed. Finally, the splitting failure mechanism of the Brazilian disc and the influencing factors of dynamic tensile strength of the frozen soils are discussed. The results indicate that under the dynamic loads, the Brazilian disc specimens of frozen clay and frozen sand follow the central initiation failure mode, and the specimens are split into two relatively intact halves along the axial direction. With the increase of the impact pressure, the loading rate of two frozen soil types increases linearly, and the duration required for reaching the dynamic tensile peak stress for them is in the range of 92~242 μs. The dynamic tensile strength of the frozen soils shows the obvious temperature effects and loading rate effects, and its values increase with the decrease of the temperature and the increase of the loading rate. There is a good linear relationship between the absorbed energy and the dynamic tensile strength of the frozen soils under various negative temperature conditions. With the increase of the impact pressure, the damage degree of the frozen soil specimens is aggravated, and the triangular fracture zone area caused by high shear stress gradually increases.

     

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