摘要
在泥炭质土软基固结过程中,孔隙比和渗透系数会随固结时间增加逐渐变小,导致按Terzaghi一维固结理论计算的软基固结值与实测值存在较大误差,故以滇池湖相沉积泥炭质土为研究对象,进行固结-渗透联合试验,研究泥炭质土e-σ′,k-σ′之间规律,从而得到e-lgσ′,lgk-lgσ′模型,然后引入这两个模型推导出适用于泥炭质土的一维非线性固结理论,并求解出渗压指数C_(k)=1,C_(k)=2两种不同条件下的解析解。根据所取泥炭质土的C_(k)不同,当C_(k)=1时,一维非线性固结微分方程的解析解与Terzaghi一维固结方程解析解比较,仅竖向固结系数存在差异;当C_(k)=2时,一维非线性固结微分方程难以直接得到解析解,可引入激活函数得到非线性固结微分方程的一个特解。研究发现,C_(k)=1时,泥炭质土固结过程中Terzaghi一维固结理论预测沉降速率比实测快,固结完成所需时间短;推导的一维非线性固结理论预测的各时间段固结沉降值和实测值接近,预测固结完成所需的时间误差小,且上覆荷载越大St-t关系曲线与实测值越接近,推导的一维非线性固结理论预测结果越精确。研究结果可为泥炭质土类软基提供一种更为精确的固结计算方法。
In the process of soft foundation consolidation of peaty soil,the pore ratio and permeability coefficient will gradually become smaller with the increase of consolidation time,that leads to a large error between the consolidation value of soft foundation calculated according to Terzaghi’s one-dimensional consolidation theory and the measured value.Taking the lake-phase sedimentary peaty soil of Dianchi Lake as the study object,the joint consolidation-permeability test is conducted to study the rule between e-σ′and k-σ′of peaty soil,so as to obtain the models of e-lgσ′and lgk-lgσ′,and these models are introduced to derive the one-dimensional nonlinear consolidation theory for peaty soil,and the analytical solutions are solved for the seepage pressure indices of C_(k)=1 and C_(k)=2 under two different conditions.According to the different C_(k) of the peaty soil,when C_(k)=1,the analytical solution of the one-dimensional nonlinear consolidation differential equation is compared with the analytical solution of the Terzaghi one-dimensional consolidation equation and only the vertical consolidation coefficient differs,when C_(k)=2,it is difficult to obtain the analytical solution of the one-dimensional nonlinear consolidation differential equation directly,and the activation function can be introduced to obtain a special solution of the nonlinear consolidation differential equation.It is found that(1)when C_(k)=1,the settlement rate predicted by Terzaghi’s one-dimensional consolidation theory is faster than the measured one during the consolidation of peaty soil,and the time required for the completion of consolidation is shorter than the measured one;(2)the values of the consolidation settlement predicted by the one-dimensional nonlinear consolidation theory are close to the measured ones,and the time error required for the completion of the predicted consolidation is small,and the larger the overburden load is the closer the St-t curve is to the measured one,and the results of onedimensional nonlinear consolidation theory predicted by Terzaghi’s one-dimensional nonlinear consolidation theory are closer to the measured one.The larger the overburden load,the closer the St-t curve is to the measured value,and the more accurate the prediction result of one-dimensional nonlinear consolidation theory is.The results can provide a more accurate consolidation calculation method for peaty soil soft foundation.
作者
阮永芬
张福禄
乔文件
吴龙
谈燕
RUAN Yong-fen;ZHANG Fu-lu;QIAO Wen-jian;WU Long;TAN Yan(School of Architectural Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650500,China;No.5 Engineering Co.,Ltd.of China Railway 20th Bureau Group,Kunming,Yunnan 650000,China;Urban Rail Engineering Co.,Ltd.of China Railway 11th Bureau Group,Wuhan,Hubei 430074,China;Yunnan Kelun Engineering Quality Inspection Co.,Ltd.,Kunming,Yunnan 650228,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2024年第2期69-78,共10页
Journal of Highway and Transportation Research and Development
基金
云南省重点研发计划项目(2018BC008)。
关键词
道路工程
非线性固结理论
固结-渗透联合试验
泥炭质土
土力学
渗透系数
road engineering
nonlinear consolidation theory
consolidation-permeability joint test
peat soil
soil mechanics
permeability coefficient
