【摘要】 从北京地铁实际的运营环境出发,通过数值计算,分析地铁区间隧道衬砌结构的纵向温度应力,探讨地铁区间隧道伸缩缝的设置间距和设置宽度。研究结果表明:温降引起的拉应力对隧道结构安全和使用功能影响显著;衬砌结构纵向温度应力与温度荷载、材料弹性模量呈线性关系;水平外约束对隧道端部(或伸缩缝)附近一定长度的衬砌结构温度应力分布产生一定影响;典型设计参数条件下的北京地铁区间隧道,其衬砌结构能承受7℃左右的温降荷载,当温降荷载超过7℃后,混凝土衬砌结构可能产生环向受拉裂缝;在实际工程中,对衬砌结构温度应力可采用环控技术和设置伸缩缝2种方法进行综合控制,以保证结构安全。针对北京地铁情况,建议伸缩缝设置间距取80~120 m、设置宽度取20~30 mm。更多还原

【Abstract】 According to the actual operation environment of subway tunnels in Beijing Metro,the longitudinal thermal stress of subway tunnel lining structure is analyzed by numerical calculation.The spacing and the width for setting expansion joint of the subway tunnel are also discussed.The research results show that the tensile stress caused by the decrease of temperature has notable effect on the safety and service function of the lining structure.The longitudinal thermal stress of the lining structure changes linearly with the change of the temperature load and the elastic modulus of material.The level constraints have definite influence on the distribution of thermal stress of the lining structure with certain length near the tunnel ends(expansion joints).For Beijing Metro tunnel under the condition of typical design parameters,its lining structure can bear the temperature decrease load of about 7 ℃.When the temperature decrease load exceeds 7 ℃,the concrete lining structure may produce some circumferential tension cracks.In practical engineering,the thermal stress of the lining structure can be comprehensively controlled by adopting environment control technology or setting the expansion joints so as to guarantee the safety of the structure.According to the condition of Beijing Metro,it is suggested that the spacing of expansion joints should be 80～120 m,and the width of the expansion joints should be 20～30 mm.更多还原