砂岩在热湿循环作用下的卸荷损伤本构模型研究
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摘要
针对在夏季高温多雨季节库岸边坡岩体的强度和稳定性下降问题,较多学者对干燥—饱水两种极端状态的循环作用进行了研究,这与实际情况相差较大。以三峡库区重庆段某典型边坡砂岩为研究对象,采用烘干—浸泡循环作用方式模拟岩石热湿循环过程,在前期进行的热湿循环试验方案及数据分析的基础上,定量对砂岩的劣化程度进行划分,对热湿循环作用下砂岩的卸荷损伤本构模型进行研究。研究结果表明:热湿循环10次内砂岩各力学参数的劣化效应比较明显,10～50次逐渐减弱并趋于平缓;基于热湿循环和卸荷相互作用,建立了完整砂岩在不同热湿循环次数下的卸荷损伤模型并绘制模型曲线;经过验证,模型曲线与试验所得的三轴卸荷应力-应变曲线吻合度较高,认为该模型具有较好的适用性。
For the problem of the decreases of the strength and stability of the slope rock mass on reservoir bank during the high temperature and rainy season of summer,many studies focus on the effect of the cycle of the two extreme states from the dry to the saturated,but it is quite different from that of the actual condition. By taking a typical slope sandstone of Chongqing Section of the Three Gorges Reservoir Area as the study object,the mode of the effect of the drying—soaking effect is adopted to simulate the process of the heat-wet cycle of the rock,and then the deterioration degree of the sandstone is quantitatively divided on the basis of the heat-wet cycle experiment scheme and the data analysis carried out during the early phase,while the constitutive model for the unloading damage of the sandstone therein under the effect of heat-wet cycle is made as well. The study result shows that the degradation effect on all the mechanical parameters of sandstone within the heat-wet cycle in 10 times is more obvious,which is gradually weakened and tends to be smooth during the cycle in 10 ～ 50 times. Under the condition of considering the interaction between the heat-wet cycle and the unloading effect,the unloading damage model for the intact sandstone under different heat-wet cycle times is established and the relevant model curve is drawn as well. It is verified that the model curve is highly coincided with the triaxial unloading stress-strain curve obtained from the experiment,thus it is considered that the model has a better applicability.
For the problem of the decreases of the strength and stability of the slope rock mass on reservoir bank during the high temperature and rainy season of summer,many studies focus on the effect of the cycle of the two extreme states from the dry to the saturated,but it is quite different from that of the actual condition. By taking a typical slope sandstone of Chongqing Section of the Three Gorges Reservoir Area as the study object,the mode of the effect of the drying—soaking effect is adopted to simulate the process of the heat-wet cycle of the rock,and then the deterioration degree of the sandstone is quantitatively divided on the basis of the heat-wet cycle experiment scheme and the data analysis carried out during the early phase,while the constitutive model for the unloading damage of the sandstone therein under the effect of heat-wet cycle is made as well. The study result shows that the degradation effect on all the mechanical parameters of sandstone within the heat-wet cycle in 10 times is more obvious,which is gradually weakened and tends to be smooth during the cycle in 10 ～ 50 times. Under the condition of considering the interaction between the heat-wet cycle and the unloading effect,the unloading damage model for the intact sandstone under different heat-wet cycle times is established and the relevant model curve is drawn as well. It is verified that the model curve is highly coincided with the triaxial unloading stress-strain curve obtained from the experiment,thus it is considered that the model has a better applicability.
引文
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[16] LEMAITRE J,CHABOCHE J L. Mechanics of solid materials[M].Cambridge:Cambridge University Press,1990.
[2] KALKAN E. Impact of wetting-drying cycles on swelling behavior of clayey soils modified by silica fume[J]. Applied clay science,2011,52(4):345-352.
[3]杨礼宁,姜振泉,张卫强,等.高温作用后砂岩力学性质研究[J].地震工程学报,2016,38(2):299-302.
[4] OBERT L,WINDES S L,DUVALL W I. Standardized test for determining the physical properties of mine rock[R]. East Lansing:U. S. Bureau of Mines,1946.
[5]向力,王乐华,陈招军,等.干湿循环作用下砂岩的劣化及破坏特性研究[J].水利水电技术,2017,48(5):142-147.
[6]张悼元,王士天,王兰生.工程地质分析原理(第二版)[M].北京:地质山版社,1994.
[7]孟召平,潘结南,刘亮壳,等.含水量对沉积岩力学性质及其冲击倾向性的影响[J].岩石力学与工程学报,2009,28(A01):2637-2643.
[8]张鹏,柴肇云.干湿循环条件下砂岩强度劣化试验研究[J].金属矿山,2013,42(10):5-7,11.
[9]王莎莎,谢学斌,肖崇春,等.考虑干湿循环效应的砂岩边坡稳定性研究[J].矿冶工程,2015,35(6):20-24.
[10]姚华彦,朱大勇,周玉新,等.干湿交替作用后砂岩破裂过程实时观测与分析[J].岩土力学,2013,32(2):329-336.
[11]傅晏.干湿循环水岩相互作用下岩石劣化机理研究[D].重庆:重庆大学,2010.
[12]邓华锋,李建林,朱敏,等.饱水-风干循环作用下砂岩强度劣化规律试验研究[J].岩土力学,2012,33(11):3306-3312.
[13]王军保,刘新荣,刘俊,等.砂岩力学特性及其改进DuncanChang模型[J].岩石力学与工程学报,2016,35(12):2388-2397.
[14]王乐华,金晶,张冰祎,等.热湿循环作用下砂岩加卸荷力学特性研究[J].岩石力学与工程学报,2018,37(3):699-708.
[15]王乐华,金晶,赵二平,等.热湿作用下三峡库区典型砂岩劣化效应研究[J].长江科学院院报,2017,34(6):76-80.
[16] LEMAITRE J,CHABOCHE J L. Mechanics of solid materials[M].Cambridge:Cambridge University Press,1990.