【摘要】 介绍编制的悬浮隧道管壁正截面轴力-弯矩曲线、弯矩-曲率曲线计算程序,论述了程序原理及逻辑流程,验证了程序的准确性;并分析了6种不同复合截面力学特性、3个截面在火灾作用下力学特性的变化及UHPC新型材料的参数敏感性。结果表明:双壳截面轴力-弯矩曲线包络面积和抗弯承载力最大,全UHPC配筋截面抗压承载能力最高,钢壳素混凝土截面延性最好。外包钢壳或UHPC使截面轴力-弯矩曲线包络面积、抗压承载力、抗弯承载力及曲率延性得到提高。在外包UHPC材料钢筋混凝土截面中,考虑UHPC抗拉强度较不考虑的抗弯承载力提高1.31%。随着外包UHPC厚度增大,截面抗弯承载力提高,然而延性系数却先增后减。随着UHPC强度增大,截面的抗弯承载力及延性系数都近似线性提高。在火灾作用下前20 min内,截面抗弯承载力及延性系数下降速度较快;防火板在前40 min内可有效减缓二者下降速度。更多还原

【Abstract】 We introduced the calculation program of the axial force-bending moment curve and bending moment-curvature curve of the normal section of the tube wall of the submerged floating tunnel, discussed the principle and logic flow of the program, then the verified the accuracy of the program, and analyzed the mechanical characteristics of six different wall sections and the changes of mechanical characteristics of three sections under fire and the parameter sensitivity of the new UHPC material. The results show that the envelope area and flexural capacity of axial force-bending moment curve of double shell section are the largest, the compressive capacity of UHPC reinforced section is the highest, and the ductility of steel shell plain concrete section is the best. The envelope area of axial force-bending moment curve, compressive bearing capacity, flexural bearing capacity and curvature ductility of the section can be improved by the outer steel shell or UHPC. In the reinforced concrete section with UHPC material, the flexural capacity is increased by 1.31% when considering the tension of UHPC compared with not considering. With the increase of the thickness of the outer UHPC, the flexural capacity of the section increases, but the ductility coefficient increases first and then decreases. With the increase of UHPC strength, the flexural capacity and ductility coefficient of the section increase approximately linearly. In the first 20 minutes under the action of fire,the flexural capacity and ductility coefficient of the section decrease rapidly; the fire board can effectively slow down the decline speed of both in the first 40 minutes.更多还原