Abstract：Foundation pit excavation is constructed in intact soil strata. So，the stress path of soil is different from that in conventional retaining wall and in conventional triaxial compression test. In foundation pit engineering，in the soil in front of and behind retaining wall，the mean principal stress p or some principal stresses decrease in excavation，generally. As a result，the negative excess hydrostatic pressure in consolidated undrained(CU) triaxial test of saturated soil will conduct，that has effects on strength parameters of soil. It is pointed out that，for the excavation in clay soil，earth pressure calculation and stability analysis using strength parameters of CU triaxial test or consolidated quick shear test are unsafe under conditions of under-consolidation soil foundation and overcharge q which is applied recently. Meanwhile，in checkings of anti-sliding stability，anti-overturning stability and global stability by Swedish circle method for gravity cement-soil wall，if the strength parameters of saturated clay soil in CU triaxial test are adopted，the gravity of soil and wall in the calculation of resistant force has to be calculated by buoyant unit. According to the discussion on Technical specification for retaining and protection of building foundation excavations(JGJ120–201×)，the action of water pressure in calculation of excavation support structure is discussed；and it is proposed that for the silt soil foundation，whether the water pressure and earth pressure are estimated together or separately lies on the properties of the under soils.
李广信. 基坑中土的应力路径与强度指标以及关于水的一些问题[J]. 岩石力学与工程学报, 2012, 31(11): 2269-2275.
LI Guangxin. STRESS PATH AND STRENGTH PARAMETERS OF SOIL IN FOUNDATION PITS AND SOME PROBLEMS ABOUT WATER. , 2012, 31(11): 2269-2275.
[1] 中华人民共和国行业标准编写组. JGJ 120—201? 建筑基坑支护技术规范[S]. 报批稿.(The Professional Standards Compilation Group of People?s Republic of China. JGJ 120—201? Technical Specification for retaining and protection of building foundation excavation[S]. Draft Standard for Approval.(in Chinese))
[2] 李广信，高等土力学[M]. 北京：清华大学出版社，2004：4–6.(LI Guangxin. Advanced soil mechanics[M]. Beijing：Tsinghua University Press，2004：4–6.(in Chinese))
[3] 中华人民共和国国家标准编写组. GB 50007—2011建筑地基基础设计规范[S]. 北京：中国建筑工业出版社，2011.(The State Standards Compilation Group of People?s Republic of China. GB 50007—2011 Code for design of building foundation[S]. Beijing：China Architecture and Building Press，2011.(in Chinese)).
[4] 李广信，有效自重压力下预固结的三轴不排水试验[J]. 工程勘察，2010，138(12)：1–4.(LI Guangxin. Undrained triaxial tests with pre- consolidation under effective overburden pressure[J]. Geotechnical Investigation and Surveying，2010，138(12)：1–4. (in Chinese)).
[5] WINTERKORN H F，FANG H Y. Foundation engineering handbook[M]. [S. l.]：Van Nostrand Reinhold Company，1975：427.
[6] 闫澍旺，封晓伟，侯晋芳，等. 用十字板强度推算软黏土抗剪强度指标的方法及应用[J]. 岩土工程学报，2009，31(12)：1 805– 1 810.(YAN Shuwang，FENG Xiaowei，HOU Jinfang，et al. Deduction and application of strength parameters of soft clay by use of vane strength[J]. Chinese Journal of Geotechnical Engineering，2009，31(12)：1 805–1 810(in Chinese))
[7] 中华人民共和国行业标准编写组. JGJ 120—99 建筑基坑支护技术规范[S]. 北京：中国建筑工业出版社，1999.(The Professional Standards Compilation Group of People?s Republic of China. JGJ 120—99 Technical specification for retaining and protection of building foundation excavation[S]. Beijing：China Architecture and Building Press，1999.(in Chinese))
[8] 中华人民共和国行业标准编写组. DG/TJ08–61—2010基坑工程技术规范[S]. 上海：上海市建筑建材业市场管理总站，2010.( The Professional Standards Compilation Group of People?s Republic of China. DG/TJ08–61—2010 Technical code for excavation engineering[S]. Shanghai：Shanghai Construction and Construction Material Industry Administration Department，2010.(in Chinese))
2012, Vol. 31 
