【摘要】 钢筋混凝土顶管施工技术广泛应用于排水管道、电力管道等城市基础设施建设,当其需要长距离穿越江河底部时,会面临上覆土层厚度变化显著、江底水头压力大和江边环境影响敏感等问题。本文结合上海白龙港南线输送干线大直径顶管穿越黄浦江段工程,建立了综合考虑上覆土层变化及江底水头压力的数值模型。采用模拟顶管机头迎面压力和管土摩擦作用的方法进行分析评估,研究了顶管端面压力、减阻泥浆模量、管土摩阻力及减阻效果等参数对地层土体变形与施工状况的影响,探讨了下穿江堤对堤坝桩基变形的影响。结果表明,由于上覆土厚度变化及水压力作用,顶管端面压力应小于机头中心土体自重应力;提高泥浆模量,降低摩擦系数,可减小顶管上方土体和结构的沉降。更多还原

【Abstract】 The reinforced concrete pipe jacking technology is widely used in the construction of urban infrastructure such as drainage pipes and power pipes. It would face several problems such as significant changes in the thickness of the overburden layer, high water pressure at the bottom of the river and the sensitive environmental impact of the riverside during long distance jacking at the bottom of river. Combined with the large-diameter pipe jacking of the main line of the Shanghai Bailonggang South Line crossing the Huangpu River section, a numerical model which comprehensively consider the overburden changes and the pressure at the bottom of the river was established. The effects of parameters such as excavation face support pressure, drag reduction mud modulus, pipe friction and drag reduction on the soil deformation and construction conditions of the stratum,were studied and the influence of the lower river embankment on the deformation of the dam foundation were discussed with the method of simulating the head pressure and pipe friction of the pipe jacking head. The research showed that due to the thickness variation of the overlying soil and the water pressure, the supporting pressure of the excavation face should be less than the self-weight stress of the excavated body at the center of the head and the settlement of the soil and structure above the top pipe could be reduced by increasing the mud modulus and reducing the friction coefficient.更多还原