[1]严红霞,韩文君,孙信,等.真空预压技术加固夹砂软土地基试验[J].林业工程学报,2019,4(05):140-145.[doi:10.13360/j.issn.2096-1359.2019.05.020]
 YAN Hongxia,HAN Wenjun,SUN Xin,et al.Field tests on soft soils with deep sand layer by vacuum preloading[J].Journal of Forestry Engineering,2019,4(05):140-145.[doi:10.13360/j.issn.2096-1359.2019.05.020]
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真空预压技术加固夹砂软土地基试验()
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《林业工程学报》[ISSN:1001-8081/CN:32-1160/S]

卷:
4
期数:
2019年05期
页码:
140-145
栏目:
森林工程与土建
出版日期:
2019-09-16

文章信息/Info

Title:
Field tests on soft soils with deep sand layer by vacuum preloading
文章编号:
2096-1359(2019)05-0140-06
作者:
严红霞1韩文君2孙信3吕伟华4
1.常州工程职业技术学院,江苏 常州 213164; 2.常州市轨道交通发展有限公司,江苏 常州 213022; 3.江苏交通控股有限公司,南京 210016; 4.南京林业大学土木工程学院,南京 210037
Author(s):
YAN Hongxia1 HAN Wenjun2 SUN Xin3 LYU Weihua4
1.Changzhou Institute of Engineering Technology, Changzhou 213164, Jiangsu, China; 2.Changzhou Rail Transportation Development Co., Ltd.,Changzhou 213022, Jiangsu, China; 3.Jiangsu Communications Holding Co., Ltd., Nanjing 210016, China; 4.College of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China
关键词:
软土地基 粉质砂土层 真空预压法 高压旋喷桩 原位测试
Keywords:
soft soil foundation silty sand layer vacuum preloading high pressure jet grouting pile in situ testing
分类号:
TU472
DOI:
10.13360/j.issn.2096-1359.2019.05.020
文献标志码:
A
摘要:
真空预压法是一种有效加固软土的地基处理方法,但工程中常因地基土中含有透水层而影响了真空荷载向深部传递,进而影响该工法的应用效果。以江海高速真空预压试验段为工程应用背景,利用孔压静力触探(CPTU)技术测定地基土中粉质砂土层厚度和深度,当采用高压旋喷桩密封处理粉质砂土层时,结合真空度、水位、孔隙水压力、地表沉降等现场实测数据,通过对比分析加固前后部分软土物理力学特性的变化对真空预压法加固效果进行了评价。结果表明:CPTU测试技术准确测得该试验场地粉质砂土层埋深介于9.5~12.5 m,将高压旋喷桩的设计深度优化至8~14 m,有效节约工程造价。加固后深部软土的强度显著提高,土体的含水量与压缩系数较加固前显著降低,平均降幅分别达11%和24.8%,综合场地地下水位、孔隙水压力的监测分析,验证了真空预压结合高压旋喷桩技术对含有粉质砂土层的软基加固的良好处置效果,可为类似工程建设和相关研究提供参考和借鉴。
Abstract:
There are many soft soil foundations along the eastern coast of China.Building infrastructure facilities on such foundation encounter many problems, such as insufficient bearing capacity, excessive settlement during construction and after-construction, and excessive differential settlement, etc.Although there are many methods to treat these soft soil foundations, such as replacement, dynamic compaction, as well as replacement and pile-based composite foundation, the vacuum preloading technology has been widely accepted as a preferential treatment method for soft soil foundations to obtain a better reinforcement effect, economy and safety.However, there are still some imperfect aspects of the method itself.For example, the vacuum load transferred to the deep strata is always mitigated if there exist aquifers in the foundation soil.This indicates that the effective transmission of vacuum degree is weakened due to the existence of permeable sand layer.In this study, the Jianghai highway vacuum preloading test section was regarded as an engineering application background, and a new method using the pore pressure static cone penetration test was proposed to determine the thickness and depth of the aquifer layer.Also, a high pressure jet grouting pile is used to seal the silty sand layer.In the field test, the land subsidence, groundwater table, porewater pressure and the vacuum degree were monitored and analyzed systematically.Results indicate that a depth of the silty sand layer from 9.5 to 12.5 m is determined by the pore pressure static cone penetration test.After evaluating the groundwater table and pore water pressure, monitored results show that the high pressure jet grouting piles have a good sealing effect so that the main settlements are eliminated effectively by the vacuum preloading at deep soft foundation.The shear strength and bearing capacity are significantly increased after preloading when comparing the laboratory and in-situ test results.Physical and mechanical properties of the soft soil are greatly improved after being consolidated due to vacuum treatment.As the strength is increased, the average gravity of treated soil is increased by 2.6%, as well as the water content and compression coefficient are evenly decreased by 11% and 24.8%, respectively.Based on this method, the treatment effect of soft soil foundation with silty sand layer is satisfactory, which provides a reference for similar engineering construction.

参考文献/References:

[1] 刘汉龙, 赵明华.地基处理研究进展[J].土木工程学报, 2016, 49(1): 96-115.DOI:10.15951/j.tmgcxb.2016.01.012.
LIU H L, ZHAO M H.Review of ground improvement technical and its application in China[J].China Civil Engineering Journal, 2016,49(1): 96-115.
[2] 陈金洪, 贺瑶瑶, 胡亚风.粒化高炉矿渣-氧化镁固化连云港软土的力学特性试验[J].林业工程学报, 2019, 4(2):133-138.DOI:10.13360/j.issn.2096-1359.2019.02.021.
CHEN J H, HE Y Y, HU Y F.Experimental study of mechanical and microstructural properties of Lianyungang soft soil solidified by granulated blast-furnace slag-magnesium oxide[J].Journal of Forestry Engineering, 2019, 4(2): 133-138.
[3] INDRARATNA B, GENG X Y, RUJIKIATKAMJORN C.Review of methods of analysis for the use of vacuum preloading and vertical drains for soft clay improvement[J].Geomechanics and Geoengineering, 2010, 5(4): 223-236.
[4] 武亚军, 顾赛帅, 强小兵, 等.基于骨架构建药剂真空预压法加固超软土试验[J].浙江大学学报(工学版), 2018, 52(4): 735-743.DOI:10.3785/j.issn.1008-973x.2018.04.017.
WU Y J, GU S S, QIANG X B, et al.Experimental study on ultra-soft soil reinforced by vacuum preloading with flocculation based on skeleton construction[J].Journal of Zhejiang University(Engineering Science), 2018, 52(4): 735-743.
[5] 杨司盟, 温智力, 刘志明, 等.絮凝联合真空预压处理吹填土的试验及机理[J].科学技术与工程, 2018, 18(27): 198-204.
YANG S M, WEN Z L, LIU Z M, et al.Experimental and mechanism study on treatment of dredger filling with flocculation and vacuum preloading[J].Science Technology and Engineering, 2018, 18(27): 198-204.
[6] NI P P, XU K, MEI G X, et al.Effect of vacuum removal on consolidation settlement under a combined vacuum and surcharge preloading[J].Geotextiles and Geomembranes, 2019, 47(1): 12-22.DOI:10.1016/j.geotexmem.2018.09.004.
[7] CHU J, YAN S W, INDRARANATA B.Vacuum preloading techniques-recent developments and applications[C]//New Orleans L A.American Society of Civil Engineers, 2008:586-595.
[8] CHAI J C, CARTER J P, HAYASHI S.Vacuum consolidation and its combination with embankment loading[J].Canadian Geotechnical Journal, 2006, 43(10): 985-996.DOI:10.1139/t06-056.
[9] 孙立强, 闫澍旺, 李伟.真空-堆载联合预压加固吹填土地基有限元分析法的研究[J].岩土工程学报, 2010, 32(4): 592-599.
SUN L Q, YAN S W, LI W.Finite element analysis of reclaimed soil foundation consolidated by surcharge preloading combined with vacuum preloading[J].Chinese Journal of Geotechnical Engineering, 2010,32(4): 592-599.
[10] YAN S W, FENG X W, CHU J.Mechanism of using vacuum preloading method in improving soft clay layers[C]//Advances in Ground Improvement: Research to Practice in the United States and China 2009 US-China Workshop on Ground Improvement Technologies.Orlando F L.Geotechnical Special Publication, ASCE, 2009: 308-317.
[11] 胡利文, 王永平.真空预压淤泥搅拌墙气密性试验分析与应用技术[J].岩土力学, 2005, 26(3): 427-431.DOI:10.16285/j.rsm.2005.03.018.
HU L W, WANG Y P.Test study and application technique for airtight capacity of mixing silt wall under vacuum preloading[J].Rock and Soil Mechanics, 2005, 26(3): 427-431.
[12] 金小荣, 俞建霖, 龚晓南, 等.含承压水软基真空联合堆载预压加固试验研究[J].岩土工程学报, 2007, 29(5): 789-794.
JIN X R, YU J L, GONG X N, et al.Field tests on soft soil with confined underground water by vacuum-surcharge preloading[J].Chinese Journal of Geotechnical Engineering, 2007, 29(5): 789-794.
[13] HAN W J, LIU S Y, ZHANG D W.Field behavior of jet grouting pile under vacuum preloading of soft soils with deep sand layer[C]//GeoCongress 2012: State of the Art and Practice in Geotechnical Engineering.Geotechnical Special Publication, 2012:70-77.
[14] 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, 34(4): 591-599.
LIU S Y, HAN W J, ZHANG D W,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, 34(4): 591-599.
[15] 章定文, 韩文君, 刘松玉, 等.劈裂真空法加固软土地基的效果分析[J].岩土力学, 2012, 33(5): 1467-1472, 1478.DOI:10.16285/j.rsm.2012.05.046.
ZHANG D W, HAN W J, LIU S Y,et al.Effect analysis of a soft ground reinforced by a combined vacuum preloading and pneumatic fracturing method[J].Rock and Soil Mechanics, 2012, 33(5): 1467-1472, 1478.
[16] 韩文君.劈裂真空法加固软土地基理论与工程应用研究[D].南京:东南大学, 2012.
HAN W J.Theory study and engineering application on combined method of vacuum preloading and pneumatic fracturing for soft ground[D].Nanjing: Southeast University, 2012.

备注/Memo

备注/Memo:
收稿日期:2018-11-08 修回日期:2019-04-15
基金项目:国家自然科学基金(51508279); 江苏省自然科学基金(BK20150885); 住房和城乡建设部科学技术计划项目(2018-K4-008); 江苏省建设系统科技项目(2018ZD200)。
作者简介:严红霞,女,讲师,研究方向为地下结构工程与地基加固。E-mail: yhxhwj@163.com
更新日期/Last Update: 2019-09-10