类岩石材料充填结构面剪切特性试验研究
发布时间：2018-08-03 09:04
【摘要】：结构面是广泛分布于天然岩体中的不连续面,对岩体的力学性质和变形特性起主控作用。软弱夹层的存在对岩石结构面的剪切强度往往有较大的弱化作用并影响岩石的稳定性,本文根据Barton的20条经典剖面曲线,选取其中JRC值为3、7、15和19的曲线,采用水泥、细砂和水按26:25:10质量配比制成水泥砂浆在特制的模具里浇铸含上述4种粗糙度的结构面的类岩石试件,并分别充填砂粒、不同含水率的粘土等充填物,在0.5、1和1.5 MPa法向力作用下,在RYL-600岩石剪切流变仪上对类岩石材料充填结构面进行直剪试验,研究不同情况下充填结构面的剪切特性并分析各因素对剪切特性的影响,并采用PFC2D程序从细观角度研究了充填物对粗糙结构面剪切特性的影响。研究结果表明:(1)剪切应力-剪切位移试验曲线大致可以分为无有峰型和有有峰型,JRC值较小以及低法向应力下JRC值较大的充填结构面,主要以无有峰型为主;无充填结构和高法向应力下JRC值较大的充填结构面,主要以有有峰型为主;(2)通常情况下JRC值越大峰值剪应力也越大,由于法向应力的存在,增大了岩石结构面间的摩擦力和爬坡阻力,从而增大了结构面的剪应力。充填物对峰值剪应力有明显的弱化作用,不同含水率土的弱化作用较砂粒而言更大,充填含水土结构面中可塑态土对结构面峰值剪应力的弱化作用最为明显;(3)引入弱化系数λ后得到修正JRC-JCS模型,通过该模型计算得出的最大剪应力值的结果与试验值呈较好的线性关系;(4)通常情况下,JRC值越大,剪切过程中的法向位移也大,法向应力的存在对结构面的剪胀有一定的抑制作用,且法向应力越大这种抑制作用越明显。由于充填体的存在,结构面间的剪胀或剪缩主要取决于充填物的压缩量与凸台剪胀量之间关系,充填物压缩量大于凸台剪胀量时整体表现为剪缩,压缩量小于凸台剪胀量时整体表现为剪胀;(5)结构面剪胀模式大致可分为纯剪胀、纯剪缩和剪缩-剪胀三种模式,含充填体的结构面发生剪缩的现象明显要多于无充填的结构面,而对于粗糙度较大的结构面,剪缩-剪胀模式中占比较多;结构面的峰值强度点的剪切位移在最大剪胀点剪切位移的0.72倍处左右;(6)结构面间的微裂纹的发生主要集中在峰值剪切应力附近,以剪切裂纹为主,由于充填物的存在,减少了结构面微裂纹的产生,从而减少结构面的破坏。
[Abstract]:Structural plane is a discontinuous plane widely distributed in natural rock mass, which plays a major role in controlling the mechanical properties and deformation characteristics of rock mass. The existence of weak intercalation often weakens the shear strength of rock structural plane and affects the stability of rock. According to 20 classical section curves of Barton, the curves with JRC values of 3 ~ 715 and 19 are selected and cement is used in this paper. Fine sand and water are used to make cement mortar into a special mould at 26:25:10 mass ratio to cast rock-like specimens containing the above four roughness structural surfaces, and filling sand and clay with different moisture content, respectively, under the normal force of 0.5 ~ 1 and 1.5 MPa, respectively. A direct shear test was carried out on the filling structure surface of rock-like material on RYL-600 rock shear rheometer. The shear characteristics of the filling structural plane under different conditions were studied and the influence of various factors on the shear characteristics was analyzed. The effect of filling on shear characteristics of rough structural plane was studied by PFC2D program from a meso point of view. The results show that: (1) the experimental curves of shear stress-shear displacement can be roughly divided into filling structural planes with no peak and small peak type and large JRC value under low normal stress, mainly with no peak; The filling surfaces with large JRC value under normal stress and without filling structure are mainly of peak type. (2) the larger the JRC value is, the greater the peak shear stress is, due to the existence of normal stress. The friction force and climbing resistance between the rock structure planes are increased, thus the shear stress of the structural plane is increased. The backfill has obvious weakening effect on the peak shear stress, and the weakening effect of soil with different moisture content is greater than that of sand. The weakening effect of plastic soil on the peak shear stress of structural plane is most obvious in filling soil and water bearing structural plane. (3) the modified JRC-JCS model is obtained by introducing the weakening coefficient 位. The maximum shear stress obtained by the model has a good linear relationship with the experimental value. (4) the larger the JRC value, the greater the normal displacement in the shear process. The existence of normal stress has a certain inhibitory effect on the shear expansion of the structural plane, and the greater the normal stress is, the more obvious the inhibition is. Because of the existence of the filling body, the shear expansion or shrinkage between the structural planes mainly depends on the relationship between the compression of the filling and the shearing expansion of the convex platform. When the compression of the filling is larger than the shearing expansion of the convex platform, the overall shearing shrinkage is observed. (5) the shear expansion mode of structural plane can be roughly divided into three modes: pure shear expansion, pure shearing shrinkage and shear-shearing expansion, and the phenomenon of shearing shrinkage in the structural plane containing filling body is obviously more than that in unfilled structural plane. However, the shear-shearing expansion mode accounts for more of the structural surfaces with larger roughness. The shear displacement of the peak strength point of the structural plane is about 0.72 times that of the maximum shear expansion point. (6) the occurrence of microcracks between the structural planes is mainly near the peak shear stress, and the shear crack is the main one, due to the existence of the filling. The formation of microcracks in the structural plane is reduced, thus the damage of the structural plane is reduced.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB302
[Abstract]:Structural plane is a discontinuous plane widely distributed in natural rock mass, which plays a major role in controlling the mechanical properties and deformation characteristics of rock mass. The existence of weak intercalation often weakens the shear strength of rock structural plane and affects the stability of rock. According to 20 classical section curves of Barton, the curves with JRC values of 3 ~ 715 and 19 are selected and cement is used in this paper. Fine sand and water are used to make cement mortar into a special mould at 26:25:10 mass ratio to cast rock-like specimens containing the above four roughness structural surfaces, and filling sand and clay with different moisture content, respectively, under the normal force of 0.5 ~ 1 and 1.5 MPa, respectively. A direct shear test was carried out on the filling structure surface of rock-like material on RYL-600 rock shear rheometer. The shear characteristics of the filling structural plane under different conditions were studied and the influence of various factors on the shear characteristics was analyzed. The effect of filling on shear characteristics of rough structural plane was studied by PFC2D program from a meso point of view. The results show that: (1) the experimental curves of shear stress-shear displacement can be roughly divided into filling structural planes with no peak and small peak type and large JRC value under low normal stress, mainly with no peak; The filling surfaces with large JRC value under normal stress and without filling structure are mainly of peak type. (2) the larger the JRC value is, the greater the peak shear stress is, due to the existence of normal stress. The friction force and climbing resistance between the rock structure planes are increased, thus the shear stress of the structural plane is increased. The backfill has obvious weakening effect on the peak shear stress, and the weakening effect of soil with different moisture content is greater than that of sand. The weakening effect of plastic soil on the peak shear stress of structural plane is most obvious in filling soil and water bearing structural plane. (3) the modified JRC-JCS model is obtained by introducing the weakening coefficient 位. The maximum shear stress obtained by the model has a good linear relationship with the experimental value. (4) the larger the JRC value, the greater the normal displacement in the shear process. The existence of normal stress has a certain inhibitory effect on the shear expansion of the structural plane, and the greater the normal stress is, the more obvious the inhibition is. Because of the existence of the filling body, the shear expansion or shrinkage between the structural planes mainly depends on the relationship between the compression of the filling and the shearing expansion of the convex platform. When the compression of the filling is larger than the shearing expansion of the convex platform, the overall shearing shrinkage is observed. (5) the shear expansion mode of structural plane can be roughly divided into three modes: pure shear expansion, pure shearing shrinkage and shear-shearing expansion, and the phenomenon of shearing shrinkage in the structural plane containing filling body is obviously more than that in unfilled structural plane. However, the shear-shearing expansion mode accounts for more of the structural surfaces with larger roughness. The shear displacement of the peak strength point of the structural plane is about 0.72 times that of the maximum shear expansion point. (6) the occurrence of microcracks between the structural planes is mainly near the peak shear stress, and the shear crack is the main one, due to the existence of the filling. The formation of microcracks in the structural plane is reduced, thus the damage of the structural plane is reduced.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB302
【参考文献】
相关期刊论文 前10条
1 文继东;许万忠;刘振翔;;多层软弱夹层的牵引式滑坡稳定性分析[J];低温建筑技术;2016年09期
2 王军;罗盼;刘飞禹;胡秀青;;初始剪应力下剪切方向角对软黏土软化特性的影响[J];岩石力学与工程学报;2016年05期
3 熊祖强;江权;龚彦华;宋磊博;崔洁;;基于三维扫描与打印的岩体自然结构面试样制作方法与剪切试验验证[J];岩土力学;2015年06期
4 孙辅庭;佘成学;万利台;;充填水泥浆岩石节理峰值剪切强度模型[J];岩石力学与工程学报;2014年12期
5 黄达;黄润秋;雷鹏;;贯通型锯齿状岩体结构面剪切变形及强度特征[J];煤炭学报;2014年07期
6 曹平;何云;范祥;蒋U，
本文编号：2161265
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/2161265.html
