沿海吹填土地基真空预压加固效果现场监测分析
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摘要
温州瓯江口某吹填区道路工程采用真空预压法加固处理,利用十字板剪切试验与静力触探等原位测试方法评估其抗剪强度增长情况,结果表明土体浅部加固效果明显,但其抗剪强度增幅随深度逐步下降。对地表沉降、分层沉降以及孔隙水压力监测分析表明,真空预压在埋深10 m范围内,负压损失较小且加固效果良好;其有效影响深度在10 m以下也是存在的,但随着深度增加而逐渐减弱,在排水板底部5 m范围内的深层土体加固效果不明显。
Dredger fill foundation of a Wenzhou Oujiang road was improved by vacuum preloading. The improvement effect was evaluated by the vane shear teats and static penetration tests. The in-situ test results indicated that the shear strength value of shallow soil was obviously promoted after vacuum preloading,and the increase of shear strength was reducing with depth. According to the analysis of ground settlement,layered settlement and pore water pressure,the following conclusions can be drawn. The negative pressure loss was small and the reinforcement effect was good within the depth of 10 m. The reinforcement effect also existed below the 10 m depth,but gradually weakened as the depth increased. The reinforcement effect of deep soil within 5 m of the bottom ofthe prefabricated vertical drain was not obvious.
Dredger fill foundation of a Wenzhou Oujiang road was improved by vacuum preloading. The improvement effect was evaluated by the vane shear teats and static penetration tests. The in-situ test results indicated that the shear strength value of shallow soil was obviously promoted after vacuum preloading,and the increase of shear strength was reducing with depth. According to the analysis of ground settlement,layered settlement and pore water pressure,the following conclusions can be drawn. The negative pressure loss was small and the reinforcement effect was good within the depth of 10 m. The reinforcement effect also existed below the 10 m depth,but gradually weakened as the depth increased. The reinforcement effect of deep soil within 5 m of the bottom ofthe prefabricated vertical drain was not obvious.
引文
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[14]Chu J,Yan S W.Estimation of degree of consolidation for vacuum preloading projects[J].International Journal of Geomechanics,2005,5(2):158-165.
[2]张功新,莫海鸿,董志良,等.真空预压中真空度与孔隙水压力的关系分析[J].岩土力学,2005,26(12):1949-1952.Zhang Gongxin,Mo Haihong,Dong Zhi1iang,et al.Analysis of relationship between vacuity and pore-water pressure in vacuum preloading[J].Rock and Soil Mechanics,2005,26(12):1949-1952.(in Chinese)
[3]张庆华,汤连生,廖化荣,等.真空预压下土体有效应力增量的计算与应用[J].岩石力学与工程学报,2006,25(S2):3565-3571.Zhang Qinghua,Tang Liansheng,Liao Huarong,et al.Calculation of incremental effective stress by vacuum preloading and its application to engineering[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(S2):3565-3571.(in Chinese)
[4]赵维炳.砂井地基固结分析半解析方法的改进[J].岩土工程学报,1991,13(4):51-58.Zhao Weibing.Improvement of semi-analytic method for consolidation of foundation with sand drains[J].Chinese Journal of Geotechnical Engineering,1991,13(4):51-58.(in Chinese)
[5]陈平山,房营光,莫海鸿,等.真空预压法加固软基三维有限元计算[J].岩土工程学报,2009,31(4):564-570.Chen Pingshan,Fang Yingguang,Mo Haihong,et al.Analysis of 3D FEM for soft foundation improved by vacuum preloading[J].Chinese Journal of Geotechnical Engineering,2009,31(04):564-570.(in Chinese)
[6]张仪萍,严露,俞亚南,等.真空预压加固软土地基变形与固结计算研究[J].岩土力学,2011,32(S1):149-154.Zhang Yiping,Yan Lu,Yu Yanan,et al.Solutions for settlement and consolidation of soft ground with vacuum preloading[J].Rock and Soil Mechanics,2011,32(S1):149-154.(in Chinese)
[7]孙立强,闫澍旺,李伟,等.超软土真空预压室内模型试验研究[J].岩土力学,2011,32(4):984-990.Sun Liqiang,Yan Shuwang,Li Wei,et al.Study of super-soft soil vacuum preloading model test[J].Rock and Soil Mechanics,2011,32(4):984-990.(in Chinese)
[8]Indraratna B,Kianfar K,Rujikiatkamjorn C,Perera D.Soft clay properties for non-Darcian radial drainage with vacuum preloading,based on Rowe cell testing[J].Australian Geomechanics Journal,2014,49(4):183-190.
[9]楼晓明,范成杰,朱亚娟,等.利用原位测试结果评价真空预压的加固效果[J].岩土工程学报,2013,35(S2):511-514.Lou Xiaoming,Fan Chengjie,Zhu Yajuan,et al.Improvement effect of vacuum preloading evaluated by in-situ tests[J].Chinese Journal of Geotechnical Engineering,2013,35(S2):511-514.(in Chinese)
[10]Saowapakpiboon J,Bergado D T,Voottipruex P,et al.PVD improvement combined with surcharge and vacuum preloading including simulations[J].Geotextiles&Geomembranes,2011,29(1):74-82.
[11]Tang M,Shang J Q.Vacuum preloading consolidation of yaoqiang airport runway[J].Geotechnique,2000,50(6),613-623.
[12]Mesri G,Khan A Q.Ground Improvement Using Vacuum Loading Together with Vertical Drains[J].Journal of Geotechnical&Geoenvironmental Engineering,2012,138(6):680-689.
[13]闫澍旺,侯晋芳,程栋栋.真空预压有效加固深度的探讨[J].水利学报,2007,38(7):774-778.Yan Shuwang,Hou Jinfang,Cheng Dongdong.Effective depth of vacuum preloading for reinforcing soft soil[J].Shuili Xuebao,2007,38(7):774-778.(in Chinese)
[14]Chu J,Yan S W.Estimation of degree of consolidation for vacuum preloading projects[J].International Journal of Geomechanics,2005,5(2):158-165.