塑料排水板结合真空预压法的径向固结解析解
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摘要
塑料排水板结合真空预压的软土地基加固方法是一种经济高效并被逐渐广泛应用的地基加固方法,该方法不仅可以减少堆载预压坝体的高度,还能减少土体的侧向位移.推导的塑料排水板与真空预压结合的非线性径向固结解析解可以较好地用于该种地基加固的预测和分析.求解过程认为软土在一维固结条件下孔隙比与平均有效应力、水平渗透系数成对数线性关系,而非以前认为的一维线性关系,因排水板周围土体被扰动,所以涂抹区中水平渗透系数采用抛物线分布形式,同时还考虑真空预压对固结的作用.退化提出的解析解与前人解析解进行对比验证、完成解析解与试验结果验证,证明了该解析解的正确性.最后,分析了参数κ和C_k/C_c对固结的影响,结果表明C_k/C_c值越大,固结时间越短,κ值增大,固结时间增长.
A system of radial consolidation by combining the plastic wick drain with the vacuum preloading is one of the most popular way for soft ground improvement,which can not only reduce the height of surcharge preloading on dam,but also reduce the lateral displacement of soil.The consolidation solution of plastic wick drains and vacuum preloading based on the nonlinear relationship can well forecast and analyze this kind of ground improvement.In the process of analytical solution, the relationship between the void ratio and the mean effective stress,as well as the horizontal permeability coefficient under onedimensional consolidation is considered to be semi logarithmic linear,rather than previously thought one-dimensional linear.Because of disturbing on soil around PVD in smear zone,permeability around PVD in the zone distributes in parabolic form.Besides,the effect of vacuum preloading on consolidation is taken into consideration.This analytical solution is verified through degradation method and compared with test results.Finally,the effects ofκ,C_k/C_c are analyzed on consolidation.The results indicate that consolidation rate increases with the increasing of C_k/C_c and decreasing ofκ.
A system of radial consolidation by combining the plastic wick drain with the vacuum preloading is one of the most popular way for soft ground improvement,which can not only reduce the height of surcharge preloading on dam,but also reduce the lateral displacement of soil.The consolidation solution of plastic wick drains and vacuum preloading based on the nonlinear relationship can well forecast and analyze this kind of ground improvement.In the process of analytical solution, the relationship between the void ratio and the mean effective stress,as well as the horizontal permeability coefficient under onedimensional consolidation is considered to be semi logarithmic linear,rather than previously thought one-dimensional linear.Because of disturbing on soil around PVD in smear zone,permeability around PVD in the zone distributes in parabolic form.Besides,the effect of vacuum preloading on consolidation is taken into consideration.This analytical solution is verified through degradation method and compared with test results.Finally,the effects ofκ,C_k/C_c are analyzed on consolidation.The results indicate that consolidation rate increases with the increasing of C_k/C_c and decreasing ofκ.
引文
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[10]INDRARATNA B,RUJIKIATKAMJORN C,SATHANANTHAN I.Radial consolidation of clay using compressibility indices and varying horizontal permeability[J].Canadian Geotechnical Journal,2005,42(5):1330.
[11]SATHANANTHAN I,INDRARATNA B,RUJIKIATKAMJORN C.Evaluation of smear zone extent surrounding mandrel driven vertical drains using the cavity expansion theory[J].International Journal of Geomechanics,2008,8(6):355.
[12]WALKER R,INDRARATNA B.Vertical drain consolidation with parabolic distribution of permeability in smear zone[J].Journal of Geotechnical and Geoenvironmental Engineering,2006,132(7):937.
[13]张海丘,高广运,雷丹.考虑3种非线性关系的径向排水固结解析解[J].工程地质学报,2015,23(4):681.ZHANG Haiqiu,GAO Guangyun,LEI Dan.An analytical solution of radial consolidation considering three non-linear relationships of soft soils[J].Journal of Engineering Geology,2015,23(4):681.
[14]CHU J,YAN S W,YANG H.Soil improvement by the vacuum preloading method for an oil storage station[J].Geotechnique,2000,50(6):625.
[15]INDRARATNA B,RUJIKIATKAMJORN C,SATHANANTHAN I.Analytical and numerical solutions for a single vertical drain including the effects of vacuum preloading[J].Canadian Geotechnical Journal,2005,42(4):994.
[16]TAVENAS P,JEAN P,LEBLOND P,et al.The permeability of natural soft clays.Part II:Permeability characteristics[J].Canadian Geotechnical Journal,1983,20(4):645.
[17]WALKER R,INDRARANA B RUJIKIATKAMGORN C.Vertical drain consolidation with no-darcian flow and voilratio-dependent compressibility and permeability[J].Géotechnique,2012,62(11):985.
[18]SATHANANTHAN I,INDRARATNA B.Laboratory evaluation of smear zone and correlation between permeability and moisture content[J].Journal of Geotechnical and Geoenvitonmental Engineering,2006,132(7):942.
[2]王军,蔡袁强,符洪涛,等.新型防淤堵真空预压法室内与现场试验研究[J].岩石力学与工程学报,2014,33(6):1257.WANG Jun,CAI Yuanqiang,FU Hongtao.et al.Indoor and field experiment on vacuum preloading with new anti-clogging measures[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(6):1257.
[3]雷华阳,张文振,韩鹏,等.吹填超软土浅层真空预压加固处理前后的固结特性[J].岩土工程学报,2013,35(12):2328.LEI Huayang,ZHANG Wenzhen,HAN Peng,et al.Consolidation property of ultra-soft soils before and after treatment of surface-layer improvement by vacuum preloading[J].Chinese Journal of Geotechnical Engineering,2013,35(12):2328.
[4]INDRARATNA B,BASACK S,RUJIKIATKAMJORN C.Numerical solution of stone column-improved soft soil considering arching,clogging,and smear effects[J].Journal of Geotechnical and Geoenvitonmental Engineering,2013,139(3):377.
[5]RUJIKIATKAMJORN C,INDRARATNA B,CHU J.2D and 3Dnumerical modeling of combined surcharge and vacuum preloading with vertical drains[J].International Journal of Geotechnics,2008,8(2):144.
[6]董志良,陈平山,莫海鸿,等.真空预压法有限元计算比较[J].岩石力学与工程学报,2008,27(11):2347.DONG Zhiliang,CHEN Pingshan,MO Haihong,et al.Comparison of numerical simulation with finite element method for vacuum preloading[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(11):2347.
[7]BARRON B A.Consolidation of fine grained soil by drain wells[J].Transaction of the American Society of Civil Engineers,1948,113:718.
[8]HANSBO S.Consolidation of fine-grained soils by prefabricated drains[C]//Proceedings of the 10th International Conference of Soil Mechanics and Foundations Engineering.Stockholm:A A Balkema,1981:677-682.
[9]李菲菲,谢康和,邓岳保.考虑指数流的真空预压竖井地基固结解析解[J].中南大学学报(自然科学版),2015,146(3):1075.LI Feifei,XIE Kanghe,DENG Yuebao.Analytical solution for consolidation by vertical drains with exponential flow under vacuum preloading[J].Journal of Central South University(Science and Technology),2015,146(3):1075.
[10]INDRARATNA B,RUJIKIATKAMJORN C,SATHANANTHAN I.Radial consolidation of clay using compressibility indices and varying horizontal permeability[J].Canadian Geotechnical Journal,2005,42(5):1330.
[11]SATHANANTHAN I,INDRARATNA B,RUJIKIATKAMJORN C.Evaluation of smear zone extent surrounding mandrel driven vertical drains using the cavity expansion theory[J].International Journal of Geomechanics,2008,8(6):355.
[12]WALKER R,INDRARATNA B.Vertical drain consolidation with parabolic distribution of permeability in smear zone[J].Journal of Geotechnical and Geoenvironmental Engineering,2006,132(7):937.
[13]张海丘,高广运,雷丹.考虑3种非线性关系的径向排水固结解析解[J].工程地质学报,2015,23(4):681.ZHANG Haiqiu,GAO Guangyun,LEI Dan.An analytical solution of radial consolidation considering three non-linear relationships of soft soils[J].Journal of Engineering Geology,2015,23(4):681.
[14]CHU J,YAN S W,YANG H.Soil improvement by the vacuum preloading method for an oil storage station[J].Geotechnique,2000,50(6):625.
[15]INDRARATNA B,RUJIKIATKAMJORN C,SATHANANTHAN I.Analytical and numerical solutions for a single vertical drain including the effects of vacuum preloading[J].Canadian Geotechnical Journal,2005,42(4):994.
[16]TAVENAS P,JEAN P,LEBLOND P,et al.The permeability of natural soft clays.Part II:Permeability characteristics[J].Canadian Geotechnical Journal,1983,20(4):645.
[17]WALKER R,INDRARANA B RUJIKIATKAMGORN C.Vertical drain consolidation with no-darcian flow and voilratio-dependent compressibility and permeability[J].Géotechnique,2012,62(11):985.
[18]SATHANANTHAN I,INDRARATNA B.Laboratory evaluation of smear zone and correlation between permeability and moisture content[J].Journal of Geotechnical and Geoenvitonmental Engineering,2006,132(7):942.