广西钦崇高速公路膨胀土动力变形及动强度特性试验研究  

Experimental Study on Dynamic Deformation and Dynamic Strength Characteristics of Expansive Soil of Qinchong Expressway in Guangxi

作　　者：唐咸远 王诗海[3] 马杰灵 罗杰 TANG Xianyuan;WANG Shihai;MA Jieling;LUO Jie(School of Architecture and Traffic Engineering,Guilin University of Electronic Science and Technology,Guilin 541004,Guangxi,China;School of Civil Engineering and Architecture,Guangxi University of Science and Technology,Liuzhou 545006,Guangxi,China;Guangxi Beitou Transportation Maintenance Technology Group Co.,Ltd.,Nanning 530029,Guangxi,China)

机构地区：[1]桂林电子科技大学建筑与交通工程学院,广西桂林541004 [2]广西科技大学土木建筑工程学院,广西柳州545006 [3]广西北投交通养护科技集团有限公司,广西南宁530029

出　　处：《重庆交通大学学报（自然科学版）》2023年第5期61-69,共9页Journal of Chongqing Jiaotong University(Natural Science)

基　　金：国家自然科学基金项目(42067044)。

摘　　要：为研究膨胀土在长期循环荷载作用下的动力变形及动强度特性,对广西钦崇高速公路膨胀土开展室内动三轴试验,分析不同围压和动应力对膨胀土轴向累积变形和动强度特性的影响。研究结果表明:膨胀土轴向累积应变随振次变化关系在较小动应力时呈现稳定型发展趋势,在动应力较大时呈现破坏型发展趋势,建立了考虑稳定型和破坏型发展趋势的修正双曲线累积变形预测模型,得出了不同围压和动应力下的拟合参数;膨胀土滞回曲线倾斜程度随振次的增加而逐渐减小,形状由饱满梭形变为柳絮条状,随围压的增加滞回曲线逐渐朝动应力轴方向靠拢,斜率逐渐增大,动应变逐渐减小;膨胀土动强度随破坏振次N_(f)的增大呈现幂函数曲线衰减规律,动黏聚力c_(d)和动内摩擦角φ_(d)在半对数坐标下随lg N的增加而线性减小,且c_(d)减小速度大于φ_(d)减小速度,将动静强度指标参数进行归一化处理后,得到了膨胀土强度指标随不同破坏振次lg N变化的归一化公式。To study the dynamicd eformation and dynamic strength characteristics of expansive soil under long-term cyclic loading,the indoor dynamic triaxial tests were carried out on expansive soil of Qinchong Expressway in Guangxi.The effects of confining pressure and dynamic stress on the axial cumulative deformation and dynamic strength characteristics of expansive soil were analyzed.The research results show that the relationship between the axial cumulative strain of expansive soil and the vibration times presents a stable development trend when the dynamic stress is small,and a destructive development trend when the dynamic stress is large.A modified hyperbolic cumulative deformation prediction model considering the stable and destructive development trends is established,and the fitting parameters under different confining pressures and dynamic stresses are obtained.The inclination of hysteresis curve of expansive soil gradually decreases with the increase of vibration times.The shape of hysteresis curve changes from full shuttle to willow flocculent strip.With the increase of confining pressure,the hysteresis curve gradually approaches to the direction of dynamic stress axis,the slope gradually increases,and the dynamic strain gradually decreases.The dynamic strength of expansive soil shows a power function curve attenuation law with the increase of failure vibration times N_(f).The dynamic cohesion c_(d)and the dynamic internal friction angleφ_(d)decrease linearly with the increase of lg N in the semi-logarithmic coordinate,and the decrease rate of c_(d)is greater than that ofφ_(d).After normalizing the dynamic and static strength index parameters,the normalized formula of the strength index of expansive soil changing with different failure vibration times lg N is obtained.

关 键 词：道路工程 膨胀土 动三轴试验 累积变形 动强度特性 

分 类 号：U416.1[交通运输工程—道路与铁道工程]