摘要
槽段间接缝会导致圆形地下连续墙的环向刚度降低,但目前尚缺乏具体方法对刚度修正系数?定量取值,有必要进行深入研究。针对铣接接头地下连续墙,考虑槽段内及槽段间两个典型位置,采用施工现场的混凝土和泥浆制作了完整及含接缝的单元体试块,由力学试验获得了接缝的应力应变曲线,并采用三折线模型进行拟合。在此基础上,导得了环向刚度修正系数的计算公式,并进行了工程实例分析。研究表明:圆形地下连续墙环向刚度修正系数与槽段平均长度、接缝宽度、接缝与混凝土刚度等因素有关;当墙体环向应力较低时,环向刚度修正系数在0.485~0.514之间;环向应力超过7.37 MPa时,环向刚度修正系数值将有所提高,而环向应力达到11 MPa时,其值为0.545~0.581;采用本文获得的参数值对工程实例进行了分析,结果表明当地下连续墙环向应力较低时,采用单一的?系数可以较好考虑接缝影响,但当应力较高时,需考虑接缝非线性刚度的影响。
Since the joints between diaphragm wall panels lead to reduction of hoop stiffness in circular excavation,it is necessary to propose a method to quantitatively evaluate the hoop stiffness correction coefficient α.The stress-strain curves of joints are first measured through the mechanical experiments on specimens containing joints and then compared to those of intact concrete cubes,separately considering the two typical locations for diaphragm wall panels with milling joint,in panels and between panels.For reliability purpose,the intact concrete cubes and specimens containing joints are both produced with concrete and slurry applied from a construction site.Then,the trilinear function is introduced to best fit the measured stress-strain curves,thus the formula for the stiffness correction coefficient α is proposed and subsequently applied to a real case analysis.The results show that the value of the stiffness correction coefficient α mainly depends on the average length of panel,the width of joints as well as the stiffness of joints and concrete.The value of α ranges between 0.485~0.514 in case of low hoop stress,and turns into a rise when the hoop stress exceeds 7.37 MPa,and reaches 0.545~0.581 when it rises up to 11 MPa.Further,the calculated results based on α obtained in the site tests indicate that it is efficient when considering the effect of joints by just taking α into account when the hoop stress stays at a low level,but the nonlinear stiffness of joints should be considered when the stress is high.In conclusion,an approach for quantitatively evaluating the hoop stiffness correction coefficient α is proposed and can be further applied for engineering application purpose.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2017年第11期2132-2138,共7页
Chinese Journal of Geotechnical Engineering
基金
交通运输部建设科技项目(2013318798320)
国家自然科学基金项目(51478051)
关键词
深基坑工程
圆形地下连续墙
接缝
环向刚度修正系数
环向应力
deep excavation
circular diaphragm wall
joint
hoop stiffness correction coefficient
hoop stress
