多元复合桩加固液化土特性分析
|
摘要
为优化复合桩(即水泥土桩与碎石桩组合)加固液化土地基,通过水泥土长桩与碎石短桩、碎石长桩与水泥土短桩及水泥土长短桩复合加固液化土进行振动台试验,分析了不同加固模型超静孔隙水压力和孔压比的变化规律,记录土体表面的高度变化,揭示多元复合桩加固液化土的机理。结果显示:碎石桩在振动过程中是主要的排水渠道,其中碎石长桩与水泥土短桩复合加固液化土不同埋深处超静孔隙水压力值曲线变化不大,峰值均在4.8 kPa左右,试验结束时均在3.5 kPa左右,说明碎石长桩可以排深层水;水泥土长桩与碎石短桩复合加固液化土中浅层的超静孔隙水压力曲线基本重合,峰值在5 kPa左右,结束时在2.5 kPa,说明碎石短桩主要排中浅层水;水泥土长短桩复合加固液化土浅层土的孔压比峰值为0.7,说明其抗液化效果主要体现在浅层地基,其主要起到对土体"隔栅"分隔、抑制震陷的作用。本研究结果可为今后实际工程加固液化土提供参考和依据。
In order to optimize the composite pile(cement pile and gravel pile) to reinforce liquescent sand foundation,the shaking table tests of liquescent sand foundation reinforced by long cement pile and short gravel pile,long gravel pile and short cement pile,and long-short cement pile were conducted.The variation of the excess pore water pressure and the pore water pressure of different liquescent sand foundation models reinforced by multiple composite piles were analyzed,and the height change of soil surface was recorded to reveal the reinforced mechanism of the liquescent sand foundation reinforced by multiple composite piles.The test results show that the gravel pile is the main drainage channel in the process of vibration.The peak of the excess pore water pressure at different depth of long gravel pile and short cement pile is around 4.8 kPa,and when the test is over,the value is aroud 3.5 kPa,meaning that the long gravel pile can drain away deep water.The excess pore water pressure curves in the middle and low depth of the liquescent sand foundation reinforced by long cement pile and short gravel pile coincide basically.The peak of excess pore water pressure in different depth of long cement pile and short gravel pile is around 5 kPa and when the test is over,the value is aroud 2.5 kPa,meaning that the short gravel pile mainly drains away shallow water.The peak of pore water pressure in low depth of long-short cement pile is 0.7.The effect of the liquescent sand foundation reinforced by long-short cement pile mainly embodies in the shallow foundation and functions to separate soil-like barrier and restrain earthquake subsidence.This research may serve asa reference for liquefied soil reinforcement of practical engineering in the future.
In order to optimize the composite pile(cement pile and gravel pile) to reinforce liquescent sand foundation,the shaking table tests of liquescent sand foundation reinforced by long cement pile and short gravel pile,long gravel pile and short cement pile,and long-short cement pile were conducted.The variation of the excess pore water pressure and the pore water pressure of different liquescent sand foundation models reinforced by multiple composite piles were analyzed,and the height change of soil surface was recorded to reveal the reinforced mechanism of the liquescent sand foundation reinforced by multiple composite piles.The test results show that the gravel pile is the main drainage channel in the process of vibration.The peak of the excess pore water pressure at different depth of long gravel pile and short cement pile is around 4.8 kPa,and when the test is over,the value is aroud 3.5 kPa,meaning that the long gravel pile can drain away deep water.The excess pore water pressure curves in the middle and low depth of the liquescent sand foundation reinforced by long cement pile and short gravel pile coincide basically.The peak of excess pore water pressure in different depth of long cement pile and short gravel pile is around 5 kPa and when the test is over,the value is aroud 2.5 kPa,meaning that the short gravel pile mainly drains away shallow water.The peak of pore water pressure in low depth of long-short cement pile is 0.7.The effect of the liquescent sand foundation reinforced by long-short cement pile mainly embodies in the shallow foundation and functions to separate soil-like barrier and restrain earthquake subsidence.This research may serve asa reference for liquefied soil reinforcement of practical engineering in the future.
引文
[1]郭英,吴永娟,牛琪瑛.碎石桩加固不同密实度砂土宏观液化现象研究[J].山西建筑,2010,36(3):100-101.
[2]张艳美,张鸿儒.碎石桩设计参数对复合地基抗液化性能的影响[J].岩土力学,2008,29(5):1320-1324.
[3]郭英.水泥土桩复合地基抗液化特性的数值分析[D].太原:太原理工大学建筑与土木工程学院,2010.
[4]李培振,任红梅,吕西林,等.液化地基自由场振动台模型试验研究[J].地震工程与工程振动,2008,28(2):172-178.
[5]YOICHI Y,MASAYUKI H,ROLANDO P,et al.Liquefaction resistance of sandy soils under partially drained condition[J].Journal of Geotechnical and Geoenvironmental Engineering,2009,135(8):1032-1043.
[6]牛琪瑛,郭英,吴永娟,等.碎石桩加固不同密实度液化土的孔隙水压力变化规律探讨[J].工程力学,2010,27(增刊Ⅰ):159-163.
[7]杨庆陶.桩体加固液化砂土的振动台试验研究[D].太原:太原理工大学建筑与土木工程学院,2008.
[8]刘茜,郑西来,刘红军,等.黄河三角洲粉土液化的试验研究[J].世界地震工程,2007,23(2):161-166.
[9]牛琪瑛,张明,杨庆涛.桩体加固液化砂土模型地基沉降分析[J].工程抗震与加固改造,2009,31(6):116-119.
[10]张明.碎石桩复合地基抗液化性能低数值模拟[D].太原:太原理工大学建筑与土木工程学院,2010.
[11]刘建君.多元复合桩加固液化土模型的振动台试验研究[D].太原:太原理工大学建筑与土木工程学院,2012.
[12]罗春雷,贺建超,丁吉,等.振动桩锤沉桩过程液化特性和贯入度数值分析[J].广西大学学报:自然科学版,2011,36(6):923-929.
[13]李立军,牛琪瑛,梁仁旺,等.砂桩加固可液化地基的振动台试验研究[J].西安建筑科技大学学报,2010,42(4):557-560.
[14]NIU Q,YAN W,YANG Q.Research on liquefaction of sandy soil in shaking table test[C]//ALBERT T Y.9th Interna-tional Symposium on Environmental Geotechnology and Global Sustainable Development.Beijing:Science Press,2008:435-441.
[2]张艳美,张鸿儒.碎石桩设计参数对复合地基抗液化性能的影响[J].岩土力学,2008,29(5):1320-1324.
[3]郭英.水泥土桩复合地基抗液化特性的数值分析[D].太原:太原理工大学建筑与土木工程学院,2010.
[4]李培振,任红梅,吕西林,等.液化地基自由场振动台模型试验研究[J].地震工程与工程振动,2008,28(2):172-178.
[5]YOICHI Y,MASAYUKI H,ROLANDO P,et al.Liquefaction resistance of sandy soils under partially drained condition[J].Journal of Geotechnical and Geoenvironmental Engineering,2009,135(8):1032-1043.
[6]牛琪瑛,郭英,吴永娟,等.碎石桩加固不同密实度液化土的孔隙水压力变化规律探讨[J].工程力学,2010,27(增刊Ⅰ):159-163.
[7]杨庆陶.桩体加固液化砂土的振动台试验研究[D].太原:太原理工大学建筑与土木工程学院,2008.
[8]刘茜,郑西来,刘红军,等.黄河三角洲粉土液化的试验研究[J].世界地震工程,2007,23(2):161-166.
[9]牛琪瑛,张明,杨庆涛.桩体加固液化砂土模型地基沉降分析[J].工程抗震与加固改造,2009,31(6):116-119.
[10]张明.碎石桩复合地基抗液化性能低数值模拟[D].太原:太原理工大学建筑与土木工程学院,2010.
[11]刘建君.多元复合桩加固液化土模型的振动台试验研究[D].太原:太原理工大学建筑与土木工程学院,2012.
[12]罗春雷,贺建超,丁吉,等.振动桩锤沉桩过程液化特性和贯入度数值分析[J].广西大学学报:自然科学版,2011,36(6):923-929.
[13]李立军,牛琪瑛,梁仁旺,等.砂桩加固可液化地基的振动台试验研究[J].西安建筑科技大学学报,2010,42(4):557-560.
[14]NIU Q,YAN W,YANG Q.Research on liquefaction of sandy soil in shaking table test[C]//ALBERT T Y.9th Interna-tional Symposium on Environmental Geotechnology and Global Sustainable Development.Beijing:Science Press,2008:435-441.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心