垂直节理对黄土渗透性的影响研究
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摘要
通过室内模型试验,研究了饱和入渗条件下黄土垂直节理对土体渗透性的影响。在实验室自制试验装置,将重塑土击实后人工切割垂直节理。在土样表面均匀喷水,使水分在土样表面饱和的状态下入渗,分析节理开度对黄土中水分入渗的影响规律。试验表明:闭合节理对土体的渗透性影响很小,实际中可以不予考虑;随着节理开度的增大,节理对土体渗透性的影响逐渐趋于明显,节理成为优势渗流面。将黄土中的节理抽象为两平行板间的缝隙,节理内水的流动满足N-S方程。考虑黄土渗流的实际特点确定了边界条件,通过推导建立了黄土节理渗透系数的表达式,分析了黄土节理渗透系数随土体体积含水量变化的特点。在数值计算中,采用四边形等参元离散土体。在离散体表面规定水头边界,对节理场地的水分场变化进行了分析。分析结果与试验对比,说明该表达式可以反映黄土节理渗流的实际特点。
The influence of vertical joint on the permeability of loess was studied by model test. The test equipment was designed to load the loess. The vertical joint was also cut to simulate the real one. Spray the water evenly on the entire surface of loess,so that the water could infiltrate in a saturated situation. The fact of joint aperture was taken consideration. The model test showed that closed joint had little influence on the infiltration,and it could be ignored. With the increase of the joint aperture,the influence of joint on the permeability of loess became obvious.The joint face could be regraded as advantage seepage surface. The joint in the loess could be abstracted as the parallel plate model. The water movement in the joint followed the N-S equation. The boundary conditions were decided,considering the actual character of loess permeability. The expression was derived and proposed to describe the permeability coefficient of loess joint. Moreover,how it changed with volumetric water content was discussed. In the numerical calculation,the joint loess was divided by quadrilateral isoparametric element. The dirichlet boundary condition was given on the surface of discrete bodies,the water field of joint loess was analyzed.By comparing the results of model test and numerical analysis,the expression could reflect the seepage character of loess joint.
The influence of vertical joint on the permeability of loess was studied by model test. The test equipment was designed to load the loess. The vertical joint was also cut to simulate the real one. Spray the water evenly on the entire surface of loess,so that the water could infiltrate in a saturated situation. The fact of joint aperture was taken consideration. The model test showed that closed joint had little influence on the infiltration,and it could be ignored. With the increase of the joint aperture,the influence of joint on the permeability of loess became obvious.The joint face could be regraded as advantage seepage surface. The joint in the loess could be abstracted as the parallel plate model. The water movement in the joint followed the N-S equation. The boundary conditions were decided,considering the actual character of loess permeability. The expression was derived and proposed to describe the permeability coefficient of loess joint. Moreover,how it changed with volumetric water content was discussed. In the numerical calculation,the joint loess was divided by quadrilateral isoparametric element. The dirichlet boundary condition was given on the surface of discrete bodies,the water field of joint loess was analyzed.By comparing the results of model test and numerical analysis,the expression could reflect the seepage character of loess joint.
引文
[1]谢定义.试论我国黄土力学研究中的若干新趋势[J].岩土工程学报,2001,23(1):1-13.
[2]梁庆国,李洁,李德武,等.黄土隧道围岩分级研究的若干问题[J].岩土工程学报,2011,33(增刊1):170-176.
[3]姜海波,苏生瑞,倪万魁,等.陕北地区黄土节理对公路边坡稳定性的影响[J].工程地质学报,2006,14(3):360-364.
[4]刘小军,王铁行,韩永强,等.黄土窑洞病害调查及分析[J].地下空间与工程学报,2007,3(6):996-999.
[5]荣冠,周创兵,王恩志.裂隙岩体渗透张量计算及其表征单元体积初步研究[J].岩石力学与工程学报,2007,26(4):740-746.
[6]周创兵,叶自桐,韩冰.岩石节理面形态与水力特性研究[J].水科学进展,1997,8(3):233-239.
[7]肖维民,夏才初,王伟,等. Reynolds控制方程下粗糙节理渗流空腔模型研究[J].岩土力学,2012,33(12):3680-3688.
[8]王建秀,朱合华,杨立中.岩溶隧道长期排水对围岩渗透性的影响[J].岩土力学,2004,25(5):715-718.
[9]姚志华,陈正汉,黄雪峰,等.非饱和原状和重塑Q3黄土渗水特性研究[J].岩土工程学报,2012,34(6):1020-1027.
[10]梁燕,邢鲜丽,李同录,等.晚更新世黄土渗透性的各向异性及其机制研究[J].岩土力学,2012,33(5):1313-1318.
[11]王铁行,卢靖,张建锋.考虑干密度影响的人工压实非饱和黄土渗透系数的试验研究[J].岩石力学与工程学报,2006,25(11):2364-2368.
[12]王铁行,岳彩坤,鲁洁,等.连续降雨条件下黄土路基水分场数值分析[J].西安建筑科技大学学报(自然科学版),2007,39(5):593-597.
[2]梁庆国,李洁,李德武,等.黄土隧道围岩分级研究的若干问题[J].岩土工程学报,2011,33(增刊1):170-176.
[3]姜海波,苏生瑞,倪万魁,等.陕北地区黄土节理对公路边坡稳定性的影响[J].工程地质学报,2006,14(3):360-364.
[4]刘小军,王铁行,韩永强,等.黄土窑洞病害调查及分析[J].地下空间与工程学报,2007,3(6):996-999.
[5]荣冠,周创兵,王恩志.裂隙岩体渗透张量计算及其表征单元体积初步研究[J].岩石力学与工程学报,2007,26(4):740-746.
[6]周创兵,叶自桐,韩冰.岩石节理面形态与水力特性研究[J].水科学进展,1997,8(3):233-239.
[7]肖维民,夏才初,王伟,等. Reynolds控制方程下粗糙节理渗流空腔模型研究[J].岩土力学,2012,33(12):3680-3688.
[8]王建秀,朱合华,杨立中.岩溶隧道长期排水对围岩渗透性的影响[J].岩土力学,2004,25(5):715-718.
[9]姚志华,陈正汉,黄雪峰,等.非饱和原状和重塑Q3黄土渗水特性研究[J].岩土工程学报,2012,34(6):1020-1027.
[10]梁燕,邢鲜丽,李同录,等.晚更新世黄土渗透性的各向异性及其机制研究[J].岩土力学,2012,33(5):1313-1318.
[11]王铁行,卢靖,张建锋.考虑干密度影响的人工压实非饱和黄土渗透系数的试验研究[J].岩石力学与工程学报,2006,25(11):2364-2368.
[12]王铁行,岳彩坤,鲁洁,等.连续降雨条件下黄土路基水分场数值分析[J].西安建筑科技大学学报(自然科学版),2007,39(5):593-597.