弱胶结砂岩地基承载力深度修正系数k2试验研究  

Experimental study on depth correction factor k2 for characteristic value of bearing capacity of weakly cemented sandstone foundation

作　　者：李忠伟[1] 龚维明[1] 胡尧 刘军[1] 柳鸿博 LI Zhongwei;GONG Weiming;HU Yao;LIU Jun;LIU Hongbo(School of Civil Engineering,Southeast University,Nanjing 210096,China;Jiangsu Traffic Engineering Construction Bureau,Nanjing 210000,China)

机构地区：[1]东南大学土木工程学院,江苏南京210096 [2]江苏省交通工程建设局,江苏南京210000

出　　处：《岩土工程学报》2024年第3期596-604,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金面上项目(52178317,52078128,51878160)。

摘　　要：为探究弱胶结砂岩深度修正合理性及修正系数取值,依托南京龙潭长江大桥北锚碇大型块体基础,对25 m埋深的弱胶结砂岩持力层分别开展基岩深层和浅层平板载荷试验,得到持力层深度修正前后的地基承载力特征值,研究深度修正规律,研究结论:修正浅层载荷试验地基承载力的修正系数k2t取3.3、修正规范法地基承载力的修正系数k2c取8.0,保守考虑时可不区分未修正的承载力特征值获得途径,k2统一取3.3;深度修正后地基承载力有较大提升,说明本工程中对弱胶结砂岩承载力进行深度修正是很有必要的;对比现有规范中土质地基k2的取值规律,弱胶结砂岩的k_(2t)和k_(2c)取值较为保守,该值可为类似地质条件下的工程提供参考。To explore the rationality of depth correction value of the weakly cemented sandstone and the correction coefficient,relying on the north anchorage of large block foundation of the Yangtze River bridge in Longtan of Nanjing,the plate loading tests on deep and shallow rock of the bearing layer of weakly cemented sand stone 25 m in depth are carried out to obtain the characteristic values of bearing capacity of the foundation before and after depth correction.The depth correction rules are investigated.The results show that the correction coefficient k2t for the shallow loading tests is 3.3,and the correction coefficient k2c for the standard method is 8.0.Under conservative consideration,the method for obtaining the uncorrected characteristic values of bearing capacity is not distinguished,and k2 is uniformly 3.3.After the depth correction,the bearing capacity of foundation is greatly improved,which indicates that it is necessary to revise the bearing capacity of weakly cemented sandstone in this project.Compared with the valuing rules of k2 of soil foundation in the existing code,the values of k_(2t) and k_(2c) of weakly cemented sandstone in this study are conservative,so it may provide a reference for the projects under similar geological conditions.

关 键 词：弱胶结砂岩 承载力特征值 深度修正 平板载荷试验 

分 类 号：TU43[建筑科学—岩土工程]