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Study on the Triaxial Compression Mechanical Properties and Damage Constitutive Model of Tunnel Sandstone in Seasonal Frozen Regions
(1 Chengdu Vocational & Technical College of Industry, Chengdu 610218; 2 Sichuan College of Architectural Technology, Chengdu,Sichuan 610399; 3 China Railway 19th Bureau Group Third Engineering Co., Ltd., Shenyang 110136)
Abstract In order to study the strength and deformation laws of surrounding rocks in seasonal frozen regions, taking highway tunnels in Liaoning as the engineering background, this paper uses the MTS815.02 triaxial test system to conduct triaxial compression tests on sandstones with different numbers of freeze-thaw cycle for studying the variation law of rock mechanical parameters with numbers of freeze-thaw cycle. And then it establishes a rock statistical damage model based on the Weibull distribution function and the D-P yield criterion, followed by model verification with the experimental data. The results show that the mechanical properties of the sandstones are significantly affected by the freeze-thaw cycle, with the peak strength, elasticity modulus decreasing and the Poisson′ s ratio increasing exponentially with the freeze-thaw cycle numbers respectively, the peak strength, elasticity modulus increasing and the Poisson′ s ratio decreasing gradually with increasing of the confining pressure respectively; the statistical damage constitutive model based on the Weibull distribution, which takes into account the freeze-thaw effect, is in good agreement with the test results, verifying the accuracy and reasonableness of the model; the Weibull distribution parameters F0 and m both decrease gradually with the freeze-thaw cycles, and their changes both have a significant effect on the model theoretical curves.
Abstract：
In order to study the strength and deformation laws of surrounding rocks in seasonal frozen regions, taking highway tunnels in Liaoning as the engineering background, this paper uses the MTS815.02 triaxial test system to conduct triaxial compression tests on sandstones with different numbers of freeze-thaw cycle for studying the variation law of rock mechanical parameters with numbers of freeze-thaw cycle. And then it establishes a rock statistical damage model based on the Weibull distribution function and the D-P yield criterion, followed by model verification with the experimental data. The results show that the mechanical properties of the sandstones are significantly affected by the freeze-thaw cycle, with the peak strength, elasticity modulus decreasing and the Poisson′ s ratio increasing exponentially with the freeze-thaw cycle numbers respectively, the peak strength, elasticity modulus increasing and the Poisson′ s ratio decreasing gradually with increasing of the confining pressure respectively; the statistical damage constitutive model based on the Weibull distribution, which takes into account the freeze-thaw effect, is in good agreement with the test results, verifying the accuracy and reasonableness of the model; the Weibull distribution parameters F0 and m both decrease gradually with the freeze-thaw cycles, and their changes both have a significant effect on the model theoretical curves.
ZHANG Lili1 LANG Songjun1 DENG Lin2 ZANG Cheng3
.Study on the Triaxial Compression Mechanical Properties and Damage Constitutive Model of Tunnel Sandstone in Seasonal Frozen Regions[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(4): 95-103
2021, Vol. 58 