真空预压-注气增压加固软土地基的孔压增长与消散机制现场试验
|
摘要
真空预压法已应用于国内外大量软土地基处理工程,并取得了较多的成熟经验。基于传统的真空预压技术,联合注气增压机制,验证其加固软土地基的可行性,重点分析软土中的孔压增长、消散过程。根据真空预压-注气增压的软基处理特点,在温州市乐清湾港区北部区域吹填和软基处理工程现场进行了小规模现场试验,全程监测注气周围的孔压增长与消散机制,试验结果可对理论研究与工程应用提供参考依据。通过试验数据对比分析发现,注气将致使土体孔压逐渐上升,并在时间上严重滞后(本试验在约一个小时之后达到最大值),随后又会缓慢消散。孔隙水压力的增加,可有效提高排水效率。孔压最大值与最小值之差可达到64 kPa以上,孔压上涨速率缓慢。分析结果表明,真空联合注气软土地基处理技术,能提高排水效率,缩短工期,降低成本。
Vacuum preloading method has been widely used in soft soil foundation treatment in China and abroad,and has got much mature experience for engineering applications.In this paper,based on the traditional vacuum preloading technology and combined air-injection pressurization mechanism,the feasibility of strengthening soft ground is verified,and the process of pore pressure increase and dissipation in soft ground is emphatically analyzed.To verify the efficiency of the combined method of vacuum preloading and air injection in soft ground treatment,a suite of in-situ tests at a project of reclamation and soft foundation treatment on the Wenzhou Yueqing bay were conducted.The mechanism of pore pressure growth and dissipation around air injection was monitored in the whole process of the test.The test results can provide reference for theoretical research and engineering application.Through comparative analysis of the test data,it was found that the air injection would lead to a gradual increase of pore pressure and a serious lag in time(the maximum value of pore pressure in this test was reached after about an hour),followed by a slow dissipation.The increase of pore water pressure can effectively improve drainage efficiency.The difference between the maximum and minimum pore pressure can reach above 64 kPa,and the increase rate of pore pressure is slow.The results show that the treatment technology of soft soil foundation with vacuum injection can improve drainage efficiency,shorten construction period and reduce cost.
Vacuum preloading method has been widely used in soft soil foundation treatment in China and abroad,and has got much mature experience for engineering applications.In this paper,based on the traditional vacuum preloading technology and combined air-injection pressurization mechanism,the feasibility of strengthening soft ground is verified,and the process of pore pressure increase and dissipation in soft ground is emphatically analyzed.To verify the efficiency of the combined method of vacuum preloading and air injection in soft ground treatment,a suite of in-situ tests at a project of reclamation and soft foundation treatment on the Wenzhou Yueqing bay were conducted.The mechanism of pore pressure growth and dissipation around air injection was monitored in the whole process of the test.The test results can provide reference for theoretical research and engineering application.Through comparative analysis of the test data,it was found that the air injection would lead to a gradual increase of pore pressure and a serious lag in time(the maximum value of pore pressure in this test was reached after about an hour),followed by a slow dissipation.The increase of pore water pressure can effectively improve drainage efficiency.The difference between the maximum and minimum pore pressure can reach above 64 kPa,and the increase rate of pore pressure is slow.The results show that the treatment technology of soft soil foundation with vacuum injection can improve drainage efficiency,shorten construction period and reduce cost.
引文
[1] 杨顺安,张瑛玲,刘虎中,等.深圳地区吹填淤泥的工程特征[J].地质科技情报,1997,1:87-91.Yang Shunan,Zhang Yingling,Liu Huzhong,et al.Engineering characteristics of blow-filled soft clay in shenzhen area[J].Geological Science and Technology Information,1997,1:87-91.(in Chinese)
[2] 王清,肖树芳.海积软土的工程地质研究现状 [J].世界地质,2000,3:253-257.Wang Qing,Xiao Shufang.A review on the engineering geology of marine soft soil[J].World Geology,2000,3:253-257.(in Chinese)
[3] 房后国,刘娉慧,肖树芳,等.海积软土排水固结机理分析[J].吉林大学学报(地球科学版),2005,35(2):207-212+217.Fang Houguo,Liu Pinghui,Xiao Shufang,et al.Analysis on mechanism of drain and consolidation of marine soft soil[J].Journal of Jilin University (Earth Science Edition),2005,35(2):207-212+217.(in Chinese)
[4] 王宝勋.海积软土力学特征与固化新技术研究[D].湖南:中南大学,2008..Wang BaoXun.Study on mechanical characteristics and new solidifying technology for marine soft soil[D].Hunan:Central South University,2008.(in Chinese)
[5] 张成良,洪振舜,邓永锋.淤泥吹填处理及其研究进展[J].路基工程,2007,1:12-14.
[6] 张延军,张延诘.国内真空预压法加固软土地基的现状与趋势[J].世界地质,2000,4:375-378.Zhang Yanjun,Zhang Yanjie.Current situation and tendency of improving soft foundation by vacuum preloading[J].World Geology,2000,4:375-378.(in Chinese)
[7] 许胜,王媛.真空预压法加固软土地基理论研究现状及展望[J].岩土力学,2006,27(10):943-947.Xu Sheng,Wang Yuan.State-of-arts and prospectconsolidation theory for soft soil by vacuum preloading[J].Rock and Soil Mechanics,2006,27(10):943-947.(in Chinese)
[8] 陈环.真空预压加固软基的理论与实践[J].工业建筑,1984,1:38-43.
[9] 高志义,张美燕,刘玉饪,姜朴.真空预压加固的离心模型试验研究[J].港口工程,1988(3):45-50.
[10] 张诚厚.真空作用面位置及排水板间距对加固效果的影响[J].岩土工程学报,1990(1):56-60.Zhang Chenghou.The influence of vacuum location and the spacing of drain well on the effect of preloading improvement[J].Chinese Journal of Geotechnical Engineering,1990(1):56-60.(in Chinese)
[11] 龚晓南,岑仰润.真空预压加固软土地基机理探讨[J].哈尔滨建筑大学学报,2004,35(2):7-10.Gong Xiaonan,Cen Yangrun.Mechanism of vacuum preloading[J].Journal of Harbin University of C.E.& Architecture,2004,35(2):7-10.(in Chinese)
[12] 李青松,吴爱祥,姚振巩,等.真空渗流场的形成机理探讨[J].矿业研究与开发,2004,24(6):16-29.Li Qingsong,Wu Aixiang,Yao Zhenfan,et al.Research on the forming mechanism of vacuum seepage field[J].Mining Research and Development,2004,24(6):16-29.(in Chinese)
[13] 李青松,吴爱祥,黄继先,等.真空渗流场作用下的渗透固结[J].中南大学学报(自然科学版),2005,36(4):689-693.Li Qingsong,Wu Aixiang,Huang Jixian.Infiltrating concretion in vacuum seepage field[J].Journal of Central South University (Science and Technology),2005,36(4):689-693.(in Chinese)
[14] 彭劫,刘汉龙,陈永辉.真空一堆载联合预压法加固机理讨论[J].河海大学学报(自然科学版),2003,31(5):560-563.Peng Jie,Liu Hanlong,Chen Yonghui.Study on improvement mechanism of vacuum combined surcharge preloading[J].Journal of Hohai University (Science and Technology),2003,31(5):560-563.(in Chinese)
[15] 黄生文,贾存兴,陈智杰.真空预压的加固机理与加固深度探讨[J].中外公路,2005,25(4):47-49.
[16] 董志良,胡利文,张功新.真空及真空联合堆载预压法加固软基的机理与理论研究[J].水运工程,2005,350(9):53- 91.Dong Zhiliang,Hu Liwen,Zhang Gongxin.Theory study on vacuum and vacuum-load consolidation of soft ground[J].Port & Waterway Engineering,2005,350(9):53-91.(in Chinese)
[17] 刘松玉,韩文君,章定文,等.劈裂真空法加固软土地基试验研究[J].岩土工程学报,2012(4):591-599.Liu Songyu,Han Wenjun,Zhang Dingwen,et al.Field pilot tests on combined method of vacuum preloading and pneumatic fracturing for soft ground improvement [J].Chinese Journal of Geotechnical Engineering,2012(4):591-599.(in Chinese)
[2] 王清,肖树芳.海积软土的工程地质研究现状 [J].世界地质,2000,3:253-257.Wang Qing,Xiao Shufang.A review on the engineering geology of marine soft soil[J].World Geology,2000,3:253-257.(in Chinese)
[3] 房后国,刘娉慧,肖树芳,等.海积软土排水固结机理分析[J].吉林大学学报(地球科学版),2005,35(2):207-212+217.Fang Houguo,Liu Pinghui,Xiao Shufang,et al.Analysis on mechanism of drain and consolidation of marine soft soil[J].Journal of Jilin University (Earth Science Edition),2005,35(2):207-212+217.(in Chinese)
[4] 王宝勋.海积软土力学特征与固化新技术研究[D].湖南:中南大学,2008..Wang BaoXun.Study on mechanical characteristics and new solidifying technology for marine soft soil[D].Hunan:Central South University,2008.(in Chinese)
[5] 张成良,洪振舜,邓永锋.淤泥吹填处理及其研究进展[J].路基工程,2007,1:12-14.
[6] 张延军,张延诘.国内真空预压法加固软土地基的现状与趋势[J].世界地质,2000,4:375-378.Zhang Yanjun,Zhang Yanjie.Current situation and tendency of improving soft foundation by vacuum preloading[J].World Geology,2000,4:375-378.(in Chinese)
[7] 许胜,王媛.真空预压法加固软土地基理论研究现状及展望[J].岩土力学,2006,27(10):943-947.Xu Sheng,Wang Yuan.State-of-arts and prospectconsolidation theory for soft soil by vacuum preloading[J].Rock and Soil Mechanics,2006,27(10):943-947.(in Chinese)
[8] 陈环.真空预压加固软基的理论与实践[J].工业建筑,1984,1:38-43.
[9] 高志义,张美燕,刘玉饪,姜朴.真空预压加固的离心模型试验研究[J].港口工程,1988(3):45-50.
[10] 张诚厚.真空作用面位置及排水板间距对加固效果的影响[J].岩土工程学报,1990(1):56-60.Zhang Chenghou.The influence of vacuum location and the spacing of drain well on the effect of preloading improvement[J].Chinese Journal of Geotechnical Engineering,1990(1):56-60.(in Chinese)
[11] 龚晓南,岑仰润.真空预压加固软土地基机理探讨[J].哈尔滨建筑大学学报,2004,35(2):7-10.Gong Xiaonan,Cen Yangrun.Mechanism of vacuum preloading[J].Journal of Harbin University of C.E.& Architecture,2004,35(2):7-10.(in Chinese)
[12] 李青松,吴爱祥,姚振巩,等.真空渗流场的形成机理探讨[J].矿业研究与开发,2004,24(6):16-29.Li Qingsong,Wu Aixiang,Yao Zhenfan,et al.Research on the forming mechanism of vacuum seepage field[J].Mining Research and Development,2004,24(6):16-29.(in Chinese)
[13] 李青松,吴爱祥,黄继先,等.真空渗流场作用下的渗透固结[J].中南大学学报(自然科学版),2005,36(4):689-693.Li Qingsong,Wu Aixiang,Huang Jixian.Infiltrating concretion in vacuum seepage field[J].Journal of Central South University (Science and Technology),2005,36(4):689-693.(in Chinese)
[14] 彭劫,刘汉龙,陈永辉.真空一堆载联合预压法加固机理讨论[J].河海大学学报(自然科学版),2003,31(5):560-563.Peng Jie,Liu Hanlong,Chen Yonghui.Study on improvement mechanism of vacuum combined surcharge preloading[J].Journal of Hohai University (Science and Technology),2003,31(5):560-563.(in Chinese)
[15] 黄生文,贾存兴,陈智杰.真空预压的加固机理与加固深度探讨[J].中外公路,2005,25(4):47-49.
[16] 董志良,胡利文,张功新.真空及真空联合堆载预压法加固软基的机理与理论研究[J].水运工程,2005,350(9):53- 91.Dong Zhiliang,Hu Liwen,Zhang Gongxin.Theory study on vacuum and vacuum-load consolidation of soft ground[J].Port & Waterway Engineering,2005,350(9):53-91.(in Chinese)
[17] 刘松玉,韩文君,章定文,等.劈裂真空法加固软土地基试验研究[J].岩土工程学报,2012(4):591-599.Liu Songyu,Han Wenjun,Zhang Dingwen,et al.Field pilot tests on combined method of vacuum preloading and pneumatic fracturing for soft ground improvement [J].Chinese Journal of Geotechnical Engineering,2012(4):591-599.(in Chinese)