确定压力隧洞混凝土衬砌初裂间距的钢筋混凝土曲梁法  

A CURVED REINFORCED CONCRETE BEAM MEHTOD FOR CALCULATING INITIAL CRACK SPACE IN THE LINING OF PRESSURE TUNNELS

作　　者：彭守拙[1] 钟建文[1] 

机构地区：[1]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《工程力学》2010年第10期90-95,103,共7页Engineering Mechanics

摘　　要：压力隧洞钢筋混凝土衬砌的裂缝间距直接影响裂缝宽度,是限裂设计重要参数之一。4个现场水压试验的结果和实际经验表明:与建筑构件相比,衬砌初次开裂的特点是裂缝间距较大、条数较少。提供一个确定"初裂间距"的钢筋混凝土曲梁法,它能考虑配筋量、衬砌曲率、内水压力、围岩的法向及切向反力的作用,且计算较为简易。比较了本法和"弹性地基曲梁理论"的优缺点并进行了讨论。算例表明,两法计算结果大体一致,都能反映衬砌的初裂特点,较为符合实际。也可利用所提供的方法判断随着内水压的升高是否发生第二次开裂。The space between cracks in the concrete lining of pressure tunnel has an important effect on the crack opening. The practical results of four prototype water pressure tests indicate that less initial cracks, of relatively larger spacing, would be triggered under critical internal water pressure as compared to that of reinforced concrete members in structural engineering. A curved reinforced beam method is presented for the determination of initial crack space in the lining of pressure tunnels, which, as a simple approach, can consider the effects of lining curvature, reinforcement ratio, the internal water pressure, as well as the normal and tangential reaction forces by the surrounding rock mass. A comparison is also made between the proposed method and the theory of a bending beam on elastic foundation, and the advantages and disadvantages of both methods are discussed. A field case of a pressure tunnel is analyzed and the predictions by the two methods compare favorably and are basically in agreement with the actual cracking behavior in the lining. Moreover, the occurrence of further cracking under increasing water pressure can be determined by the proposed method.

关 键 词：地下工程 压力隧洞、钢筋混凝土衬砌 初裂间距 裂缝宽度 围岩 

分 类 号：U451.4[建筑科学—桥梁与隧道工程]