超固结软黏土一维蠕变次固结系数与侧压力系数  

One-dimensional secondary consolidation coefficient and lateral pressure coefficient of overconsolidated soft clay

作　　者：李国维[1,2] 胡坚[3,2] 陆晓岑[2] 周洋[2] 

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点试验室,江苏南京210098 [2]河海大学岩土工程科学研究所,江苏南京210098 [3]温州市交通投资集团有限公司,浙江温州325000

出　　处：《岩土工程学报》2012年第12期2198-2205,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(41272327);江苏省自然科学基金项目(BK2011747);广东省交通科技项目(200502)

摘　　要：通过K 0固结原状试样一维蠕变试验,模拟软土地基超载预压卸荷再加荷过程,研究超固结软黏土蠕变过程的次固结系数C和侧压力系数K 0r与应力历史的关系。研究结果表明,超固结软黏土的主固结过程相对于正常固结状态有明显缩短,次固结系数C与荷载相关,随着OCR增大而减小,超载预压时间延长导致OCR增大次固结系数减小。超固结软黏土蠕变过程的侧压力系数K 0r随时间近似恒定,受应力状态和应力历史影响,随再加荷压力增大而减小,随前期固结压力的增大而增大,与OCR近似成线性关系。依据试验和假定建立的K 0r理论模型,反应了相关条件的影响,无需专用参数,与试验结果具有较高的一致性。一维变形条件下,超固结软黏土的次固结系数C与广义剪应力和球应力的比值q p具有本质上的联系,符合双曲线规律。A series of one-dimensional Ko consolidation and creep tests on undisturbed samples are carried out to simulate the surcharge preloading process of unloading and reloading and to study the relationship between the secondary consolidation coefficient Ca , lateral press coefficient K0r of overconsolidated soft clay and stress history. The studies show that the primary consolidation time of the overconsolidated soft clay is much more reduced than that of the normally consolidated soft clay; the secondary consolidation coefficient is related to pressure and it becomes less as OCR increases; and longer pre-loading time makes OCR increase and Ca decrease. The lateral pressure coefficient K0r in creep process of soft clay is an approximate constant over time and it is influenced by stress state and stress history. It becomes less as reloading pressure increases and becomes larger with pre-consolidation pressure and has an approximate linear relationship with OCR. The K0r model found by experiment and hypothesis without special parameters reflects the influence of the related conditions and has high consistency with the experimental results. The secondary consolidation coefficient C, is related with the ratio of shear stress and spheric stress q/p essentially, and they meet the hyperbolic rule.

关 键 词：超固结 软黏土 蠕变 侧压力系数 

分 类 号：TU411[建筑科学—岩土工程]