摘要
为探明西北地区广泛分布的弱胶结砂岩在富水情况下的变形破坏机理,实现TBM快速掘进,首先对其力学特性进行了研究,结果表明围岩具有较明显的水致软化性质,在富水情况下岩石强度及弹性模量等力学参数会出现明显下降。采用钨灯丝扫描电子显微镜对岩样全貌、局部、孔隙的微观结构进行观察,结果表明岩石裂隙发育,由大小粒径不同的颗粒构成,裂隙由微米级的矿物填充,浸水后颗粒之间孔隙更加明显,岩块完整程度降低,能看到白色丝状的黏土矿物;数值模拟结果表明浸水前水平位移与竖向位移分别是63、112 mm,浸水后水平位移与竖向位移分别是86、182 mm,说明围岩在富水条件下变形量更大,浸水前塑性区基本全是剪切塑性区,面积达到23.22 m^(2),浸水后塑性区范围从顶底板扩散到帮部,塑性区面积急剧增大且出现拉伸破坏区,剪切塑性面积为89.87 m^(2),拉伸塑性面积为3.41 m^(2),是导致围岩顶板冒落的最危险区域,与现场实际表现出顶板冒落、帮部剥落的破坏现象相符。
In order to explore the deformation and failure mechanism of weakly cemented sandstone widely distributed in Northwest China under water-rich conditions and realize rapid TBM tunneling,the mechanical properties of weakly cemented sandstone are studied first,and the results show that the surrounding rock has obvious water-induced softening properties,and the mechanical parameters such as rock strength and elastic modulus will decrease significantly under water-rich conditions.Tungsten filament scanning electron microscope was used to observe the microstructure of the whole,local and pore of the rock sample.The results show that the rock fractures are developed and composed of particles with different particle sizes.The fractures are filled with micron-sized minerals.After soaking in water,the pores between particles are more obvious,the integrity of the rock block is reduced,and white filamentous clay minerals can be seen;The numerical simulation results show that the horizontal and vertical displacements before flooding are 63 mm and 112 mm respectively,and the horizontal and vertical displacements after flooding are 86 mm and 182 mm respectively,which indicates that the deformation of surrounding rock is larger under the condition of rich water.Before flooding,the plastic zone is basically shear plastic zone with an area of 23.22 m^(2),and after flooding,the plastic zone spreads from the roof to the floor.The area of plastic zone increases sharply and tensile failure zone appears,the shear plastic area is 89.87 m^(2),and the tensile plastic area is 3.41 m^(2),which is the most dangerous area leading to roof caving of surrounding rock,consistent with the failure phenomenon of roof caving and sides peeling in the field.
作者
谢雄耀
康鑫
周彪
李安云
康元锋
XIE Xiongyao;KA NG Xin;ZHOU Biao;LI Anyun;KA NG Yuanfeng(College of Civil Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical&Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China;Urban Rail Transit Engineering Co.,Ltd.,China Railway 15th Bureau Group,Yangzhou 225001,Jiangsu,China)
出处
《建筑施工》
2023年第11期2359-2362,共4页
Building Construction
基金
国家自然科学基金资助项目(52038008)
国家自然科学基金资助项目(51978431)
中铁十五局集团有限公司科技研发计划项目(2021A1,2021C61)。
关键词
富水
弱胶结砂岩
水致软化
破坏机理
water-rich
weakly cemented sandstone
water-induced softening
failure mechanism
