水泥固化的风积沙地基扩展基础抗拔试验研究
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摘要
沙漠风积沙地基结构松散、稳定性差、承载力低,利用水泥作为固化剂固化稳定风积沙,形成水泥固化风积沙地基是改善其不良工程特性的有效手段。将取自内蒙古库布齐沙漠的现场风积沙重塑为3%含水率的试验用风积沙,向其中掺入6%普通硅酸盐水泥经充分拌和形成水泥固化风积沙填料,完成了水泥固化风积沙地基中9个扩展基础模型抗拔试验。结果表明,风积沙水泥固化方法可显著提高风积沙抗拔承载性能。上拔荷载作用下,当水泥固化风积沙扩展基础抗拔深度与底板边长比值小于3.5时,其荷载–位移曲线呈2阶段变化:初始弹性段—峰值荷载、峰值荷载后破坏段,极限抗拔承载力对应的位移与底板边长比值变化范围为0.04%~1.05%,平均0.54%。按"土重法"确定的水泥固化风积沙"上拔角"远大于天然风积沙。
Aeolian sands are inherently very low in strength and very high in compressibility because they are loose, cohesionless and easily movable. The cement-stabilization of aeolian sand may be an alternative method to improve the mechanical characteristics of aeolian sand in the desert areas. In this study, the aeolian sand samples collected from the Hobq Desert are remoulded with a moisture content of 3%, and a relatively small amount of cement of 6% by weight of dry aeolian sand is added to the aeolian sand backfill. A total of 9 uplift load tests are carried out to investigate the uplift performance of model spread foundations embedded in cement-stabilized aeolian sand. The experimental results demonstrate that the cement-stabilized aeolian sand has a typical brittle nature, and two-phase pre-peak and post-peak behaviours of load–displacement responses are observed in all the tests on the model spread foundations embedded in the cement-stabilized aeolian sand. Under uplift loading, when the normalized embedment ratio of depth to basement width for spread foundations is less than 3.5, the displacement corresponding to the ultimate uplift resistance ranges from 0.04%~1.05% of the basement width, with an average of 0.54%. Based on the uplift capacity of shallow spread corresponding to the peak failure resistances, the magnitudes of the slope angle α of the dead weight method are calculated for each of the spread foundations. Compared to the natural aeolian sand, the significant increases in uplift resistance and slope angle α of the dead weight method can be obtained for model spread foundations subjected to uplift in the cement-stabilized aeolian sand, irrespective of embedment ratios of H/D.
Aeolian sands are inherently very low in strength and very high in compressibility because they are loose, cohesionless and easily movable. The cement-stabilization of aeolian sand may be an alternative method to improve the mechanical characteristics of aeolian sand in the desert areas. In this study, the aeolian sand samples collected from the Hobq Desert are remoulded with a moisture content of 3%, and a relatively small amount of cement of 6% by weight of dry aeolian sand is added to the aeolian sand backfill. A total of 9 uplift load tests are carried out to investigate the uplift performance of model spread foundations embedded in cement-stabilized aeolian sand. The experimental results demonstrate that the cement-stabilized aeolian sand has a typical brittle nature, and two-phase pre-peak and post-peak behaviours of load–displacement responses are observed in all the tests on the model spread foundations embedded in the cement-stabilized aeolian sand. Under uplift loading, when the normalized embedment ratio of depth to basement width for spread foundations is less than 3.5, the displacement corresponding to the ultimate uplift resistance ranges from 0.04%~1.05% of the basement width, with an average of 0.54%. Based on the uplift capacity of shallow spread corresponding to the peak failure resistances, the magnitudes of the slope angle α of the dead weight method are calculated for each of the spread foundations. Compared to the natural aeolian sand, the significant increases in uplift resistance and slope angle α of the dead weight method can be obtained for model spread foundations subjected to uplift in the cement-stabilized aeolian sand, irrespective of embedment ratios of H/D.
引文
[1]乾增珍,鲁先龙,丁士君.上拔与水平力组合作用下加筋风积沙斜柱扩展基础试验[J].岩土工程学报,2011,33(3):373–379.(QIAN Zeng-zhen,LU Xian-long,DING Shi-jun.Experiments on pad and chimney foundation in reinforced aeolian sand under uplift combined with horizontal loads[J].Chinese Journal of Geotechnical Engineering,2011,33(3):373–379.(in Chinese))
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[3]鲁先龙,程永锋.我国输电线路基础工程现状与展望[J].电力建设,2005,26(11):25–27.(LU Xian-long,CHENG Yong-feng.Current status and prospect of transmission tower foundation engineering in China[J].Electric Power Construction,2005,26(11):25–27.(in Chinese))
[4]中国电力科学研究院.复杂地质环境下输变电工程关键技术研究[R].北京:中国电力科学研究院,2014.(China Electric Power Research Institute.Report on key technology of power transmission and transformation project under complicated geological environment[R].Beijing:China Electric Power Research Institute,2014.(in Chinese))
[5]高玉生,陈汝恩,李英海,等.中国沙漠风积沙工程性质研究及工程应用[M].北京:中国水利水电出版社,2013.(GAO Yu-sheng,CHEN Ru-en,LI Ying-hai,et al.Research on the engineering property and application of aeolian sand in China[M].Beijing:Chines Water Sources and Hydroelectric Power Press,2013.(in Chinese))
[6]AIBAN S A.A study of sand stabilization in eastern saudi arabia[J].Engineering Geology,1994,38(1/2):65–79.
[7]BAGHDADI Z A,RAHMAN M A.The potential of cement kiln dust for the stabilization of dune sand in highway construction[J].Building and Environment,1990,25(4):285–289.
[8]PANWAR P,AMETA N K.Stabilization of dune sand with bentonite and lime[J].Electronic Journal of Geotechnical Engineering,2013,18:2667–2674.
[9]ELIPE M G M,LOPEZ-QUEROL S.Aeolian sands:Characterization,options of improvement and possible employment in construction-The state-of-the-art[J].Construction and Building Materials,2014,73:728–739.
[10]张涛,刘松玉,蔡国军.固化粉土小应变剪切模量与强度增长相关性研究[J].岩土工程学报,2015,37(11):1955–1964.(ZHANG Tao,LIU Song-yu,CAI Guo-jun.Relationship between small-strain shear modulus and growth of strength for stabilized silt[J].Chinese Journal of Geotechnical Engineering,2015,37(11):1955–1964.(in Chinese))
[11]郭印.淤泥质土的固化及力学特性的研究[D].杭州:浙江大学,2007.(GUO Yin.Study on stabilization of muddy soil and mechanical properties of stabilized soil[D].Hangzhou:Zhejiang University,2007.(in Chinese))
[12]李雪刚.杭州海相软土的固化及其理论研究[D].杭州:浙江大学,2013.(LI Xue-gang.Theoretical study on stabilization of marine soft clay in Hangzhou[D].Hangzhou:Zhejiang University,2013.(in Chinese))
[13]杨西锋,尤哲敏,牛富俊,等.固化剂对盐渍土物理力学性质的固化效果研究进展[J].冰川冻土,2014,36(2):376–385.(YANG Xi-feng,YOU Zhe-min,NIU Fu-jun,et al.Research progress in stabilizers and their effects in improving physical and mechanical properties of saline soil[J].Journal of Glaciology and Geocryology,2014,36(2):376–385.
[14]熊海帆.膨胀土水泥改性试验研究[D].武汉:武汉理工大学,2010.(XIONG Hai-fan.Experimental study on expansive soil modified with cement[D].Wuhan:Wuhan University of Technology,2010.(in Chinese))
[15]SARIDE S,PUPPALA A J,CHIKYALA S R.Swell-shrink and strength behaviors of lime and cement stabilized expansive organic clays[J].Applied Clay Science,2013,85:39–45.
[16]李迎春.粉土固化稳定机理与措施研究[D].南京:东南大学,2003.(LI Ying-chun.Mechanism and countermeasures of silt stabilization[D].Nanjing:Southeast University,2003.(in Chinese))
[17]王树娟.掺风积沙水泥复合土力学性能的研究[D].呼和浩特:内蒙古农业大学,2012.(WANG Shu-juan.The wind deposited sand mixed cement composite soil mechanics performance of research[D].Huhhot:Inner Mongolia Agricultural University,2012.(in Chinese))
[18]SHIRVANI R A,SHOOSHPASHA I.Experimental study on load-settlement behaviour of cement stabilised footing with different dimensions on sandy soil[J].Arabian Journal for Science and Engineering,2015,40:397–406.
[19]SL237—1999土工试验规程[S].1999.(SL237—1999Specification of soil test[S].1999.(in Chinese))
[20]AL-ANSARY M,P?PPELREITER M C,AL-JABRY A,et al.Geological and physiochemical characterization of construction sands in Qatar[J].International Journal of Sustainable Built Environment,2012,1:64–84.
[21]AL-SANAD H A,ISMAEL N F,NAYFEH A J.Geotechnical properties of dune sands in Kuwait[J].Engineering Geology,1993,34(1-2):45–52.
[22]AL-TAIE A J,AL-SHAKARCHI Y J,MOHAMMED A A.Investigation of geotechnical specifications of sand dune:a case study around Baiji in Iraq[J].International Journal of Advanced Research,2013,1(6):208–215.
[23]KHAN I H.Soil studies for highway construction in arid zones[J].Engineering Geology,1982,19(1):47–62.
[24]安建林.新疆风积沙力学性质与动力性能研究[D].西安:长安大学,2003.(AN Jian-lin.Research on the mechanical and dynamical property of aeolian sand in Xinjiang[D].Xi'an:Chang'an University,2003.(in Chinese))
[25]李万鹏.风积沙的工程特性与应用研究[D].西安:长安大学,2003.(LI Wan-peng.Research on the engineering properties and corresponding application for aeolian sand[D].Xi'an:Chang'an University,2003.(in Chinese))
[26]鲁先龙,程永锋,丁士君.风积沙地基工程性质及其输电线路基础抗拔设计[J].电力建设,2010,31(7):46–50.(LU Xian-long,CHENG Yong-feng,DING Shi-jun.Property of aeolian sand design of the uplift bearing capacity for the sand foundation of transmission line structure[J].Electric Power Construction,2010,31(7):46–50.(in Chinese))
[27]何静,申向东,董伟,等.风积沙掺量对水泥砂浆力学性能和微观结构的影响[J].硅酸盐通报,2015,34(9):2609–2613.(HE Jing,SHEN Xiang-dong,DONG Wei,et al.Influence of aeolian sand dosage on mechanical property and microstructure of cement mortar[J].Bulletin of the Chinese Ceramic Society,2015,34(9):2609–2613.(in Chinese))
[28]董伟,申向东.不同风积沙掺量对水泥砂浆流动度和强度的研究[J].硅酸盐通报,2013,32(9):1900–1904.(DONG Wei,SHEN Xiang-dong.Study on cement mortar fluidity and compressive strength by different aeolian sand dosage[J].Bulletin of the Chinese ceramic Society,2013,32(9):1900–1904.(in Chinese))
[29]DL/T 5219—2014架空输电线路基础设计技术规程[S].2014.(DL/T 5219—2014.Technical code for design of foundations of overhead transmission lines[S]2014.(in Chinese))
[30]BERADI R,LANCELLOTTA R.Stiffness of granular soil from field performance[J].Géotechnique,1991,41(1):149–157.
[31]CONSOLI N C,DALLA R F,FONINI A.Plate load tests on cemented soil layers overlaying weaker soil[J].Journal of Geotechnieal and Geoenvironmental Engineering,2009,135(12):1846–1856.
[32]PACHECO M P,DANZIGER F A B,PEREIRA C P.Design of shallow foundations under tensile loading for transmission line towers:An overview[J].Engineering Geology,2008,101(3/4):226–235.
[33]IEEE Std 691-2001.IEEE guide for transmission structure foundation design and testing[S].2001.
[34]乾增珍,鲁先龙,丁士君.塔克拉玛干沙漠输电线塔装配式基础试验研究[J].岩土力学,2011,32(8):2359–2364.(QIAN Zeng-zhen,LU Xian-long,DING Shi-jun.Experimental study of assembly foundation for transmission line tower in Taklimakan desert[J].Rock and Soil Mechanics,2011,32(8):2359–2364.(in Chinese))
[35]乾增珍,鲁先龙,丁士君.风积沙地基装配式偏心基础抗拔试验研究[J].岩土力学,2013,34(4):1097–1102,1108.(QIAN Zeng-zhen,LU Xian-long,DING Shi-jun.Field tests on pullout behavior of eccentric grillage foundation in aeolian sand[J].Rock and Soil Mechanics,2013,34(4):1097–1102,1108.(in Chinese))
[2]KULHAWY F H,TRAUTMANN C H,BEECH J F,et al.Transmission line structure foundation for uplift-compression loading[R].Palo Alto:Electric Power Research Institute USA,1983.
[3]鲁先龙,程永锋.我国输电线路基础工程现状与展望[J].电力建设,2005,26(11):25–27.(LU Xian-long,CHENG Yong-feng.Current status and prospect of transmission tower foundation engineering in China[J].Electric Power Construction,2005,26(11):25–27.(in Chinese))
[4]中国电力科学研究院.复杂地质环境下输变电工程关键技术研究[R].北京:中国电力科学研究院,2014.(China Electric Power Research Institute.Report on key technology of power transmission and transformation project under complicated geological environment[R].Beijing:China Electric Power Research Institute,2014.(in Chinese))
[5]高玉生,陈汝恩,李英海,等.中国沙漠风积沙工程性质研究及工程应用[M].北京:中国水利水电出版社,2013.(GAO Yu-sheng,CHEN Ru-en,LI Ying-hai,et al.Research on the engineering property and application of aeolian sand in China[M].Beijing:Chines Water Sources and Hydroelectric Power Press,2013.(in Chinese))
[6]AIBAN S A.A study of sand stabilization in eastern saudi arabia[J].Engineering Geology,1994,38(1/2):65–79.
[7]BAGHDADI Z A,RAHMAN M A.The potential of cement kiln dust for the stabilization of dune sand in highway construction[J].Building and Environment,1990,25(4):285–289.
[8]PANWAR P,AMETA N K.Stabilization of dune sand with bentonite and lime[J].Electronic Journal of Geotechnical Engineering,2013,18:2667–2674.
[9]ELIPE M G M,LOPEZ-QUEROL S.Aeolian sands:Characterization,options of improvement and possible employment in construction-The state-of-the-art[J].Construction and Building Materials,2014,73:728–739.
[10]张涛,刘松玉,蔡国军.固化粉土小应变剪切模量与强度增长相关性研究[J].岩土工程学报,2015,37(11):1955–1964.(ZHANG Tao,LIU Song-yu,CAI Guo-jun.Relationship between small-strain shear modulus and growth of strength for stabilized silt[J].Chinese Journal of Geotechnical Engineering,2015,37(11):1955–1964.(in Chinese))
[11]郭印.淤泥质土的固化及力学特性的研究[D].杭州:浙江大学,2007.(GUO Yin.Study on stabilization of muddy soil and mechanical properties of stabilized soil[D].Hangzhou:Zhejiang University,2007.(in Chinese))
[12]李雪刚.杭州海相软土的固化及其理论研究[D].杭州:浙江大学,2013.(LI Xue-gang.Theoretical study on stabilization of marine soft clay in Hangzhou[D].Hangzhou:Zhejiang University,2013.(in Chinese))
[13]杨西锋,尤哲敏,牛富俊,等.固化剂对盐渍土物理力学性质的固化效果研究进展[J].冰川冻土,2014,36(2):376–385.(YANG Xi-feng,YOU Zhe-min,NIU Fu-jun,et al.Research progress in stabilizers and their effects in improving physical and mechanical properties of saline soil[J].Journal of Glaciology and Geocryology,2014,36(2):376–385.
[14]熊海帆.膨胀土水泥改性试验研究[D].武汉:武汉理工大学,2010.(XIONG Hai-fan.Experimental study on expansive soil modified with cement[D].Wuhan:Wuhan University of Technology,2010.(in Chinese))
[15]SARIDE S,PUPPALA A J,CHIKYALA S R.Swell-shrink and strength behaviors of lime and cement stabilized expansive organic clays[J].Applied Clay Science,2013,85:39–45.
[16]李迎春.粉土固化稳定机理与措施研究[D].南京:东南大学,2003.(LI Ying-chun.Mechanism and countermeasures of silt stabilization[D].Nanjing:Southeast University,2003.(in Chinese))
[17]王树娟.掺风积沙水泥复合土力学性能的研究[D].呼和浩特:内蒙古农业大学,2012.(WANG Shu-juan.The wind deposited sand mixed cement composite soil mechanics performance of research[D].Huhhot:Inner Mongolia Agricultural University,2012.(in Chinese))
[18]SHIRVANI R A,SHOOSHPASHA I.Experimental study on load-settlement behaviour of cement stabilised footing with different dimensions on sandy soil[J].Arabian Journal for Science and Engineering,2015,40:397–406.
[19]SL237—1999土工试验规程[S].1999.(SL237—1999Specification of soil test[S].1999.(in Chinese))
[20]AL-ANSARY M,P?PPELREITER M C,AL-JABRY A,et al.Geological and physiochemical characterization of construction sands in Qatar[J].International Journal of Sustainable Built Environment,2012,1:64–84.
[21]AL-SANAD H A,ISMAEL N F,NAYFEH A J.Geotechnical properties of dune sands in Kuwait[J].Engineering Geology,1993,34(1-2):45–52.
[22]AL-TAIE A J,AL-SHAKARCHI Y J,MOHAMMED A A.Investigation of geotechnical specifications of sand dune:a case study around Baiji in Iraq[J].International Journal of Advanced Research,2013,1(6):208–215.
[23]KHAN I H.Soil studies for highway construction in arid zones[J].Engineering Geology,1982,19(1):47–62.
[24]安建林.新疆风积沙力学性质与动力性能研究[D].西安:长安大学,2003.(AN Jian-lin.Research on the mechanical and dynamical property of aeolian sand in Xinjiang[D].Xi'an:Chang'an University,2003.(in Chinese))
[25]李万鹏.风积沙的工程特性与应用研究[D].西安:长安大学,2003.(LI Wan-peng.Research on the engineering properties and corresponding application for aeolian sand[D].Xi'an:Chang'an University,2003.(in Chinese))
[26]鲁先龙,程永锋,丁士君.风积沙地基工程性质及其输电线路基础抗拔设计[J].电力建设,2010,31(7):46–50.(LU Xian-long,CHENG Yong-feng,DING Shi-jun.Property of aeolian sand design of the uplift bearing capacity for the sand foundation of transmission line structure[J].Electric Power Construction,2010,31(7):46–50.(in Chinese))
[27]何静,申向东,董伟,等.风积沙掺量对水泥砂浆力学性能和微观结构的影响[J].硅酸盐通报,2015,34(9):2609–2613.(HE Jing,SHEN Xiang-dong,DONG Wei,et al.Influence of aeolian sand dosage on mechanical property and microstructure of cement mortar[J].Bulletin of the Chinese Ceramic Society,2015,34(9):2609–2613.(in Chinese))
[28]董伟,申向东.不同风积沙掺量对水泥砂浆流动度和强度的研究[J].硅酸盐通报,2013,32(9):1900–1904.(DONG Wei,SHEN Xiang-dong.Study on cement mortar fluidity and compressive strength by different aeolian sand dosage[J].Bulletin of the Chinese ceramic Society,2013,32(9):1900–1904.(in Chinese))
[29]DL/T 5219—2014架空输电线路基础设计技术规程[S].2014.(DL/T 5219—2014.Technical code for design of foundations of overhead transmission lines[S]2014.(in Chinese))
[30]BERADI R,LANCELLOTTA R.Stiffness of granular soil from field performance[J].Géotechnique,1991,41(1):149–157.
[31]CONSOLI N C,DALLA R F,FONINI A.Plate load tests on cemented soil layers overlaying weaker soil[J].Journal of Geotechnieal and Geoenvironmental Engineering,2009,135(12):1846–1856.
[32]PACHECO M P,DANZIGER F A B,PEREIRA C P.Design of shallow foundations under tensile loading for transmission line towers:An overview[J].Engineering Geology,2008,101(3/4):226–235.
[33]IEEE Std 691-2001.IEEE guide for transmission structure foundation design and testing[S].2001.
[34]乾增珍,鲁先龙,丁士君.塔克拉玛干沙漠输电线塔装配式基础试验研究[J].岩土力学,2011,32(8):2359–2364.(QIAN Zeng-zhen,LU Xian-long,DING Shi-jun.Experimental study of assembly foundation for transmission line tower in Taklimakan desert[J].Rock and Soil Mechanics,2011,32(8):2359–2364.(in Chinese))
[35]乾增珍,鲁先龙,丁士君.风积沙地基装配式偏心基础抗拔试验研究[J].岩土力学,2013,34(4):1097–1102,1108.(QIAN Zeng-zhen,LU Xian-long,DING Shi-jun.Field tests on pullout behavior of eccentric grillage foundation in aeolian sand[J].Rock and Soil Mechanics,2013,34(4):1097–1102,1108.(in Chinese))