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一、现场状况及方案的选择欢喜岭兴隆台φ529低压输气管道经过大凌河,需要从河床下面通过。设计要求管道顶埋深为1.5米～2.5米,穿越长度为540米,套管为φ720×8,工作管为φ529×8,总重145吨,并要灌注水泥砂浆及打桩。设计的施工图给出下述资料:河床有20米厚的流砂层,是一条季节性的河流,洪水期流速可达4米/秒,主河道流移不定,河床冲刷严重,并提供了河的两岸土质情况。在设计给出资料的基础上,我有关人员进行了现场勘察,了解到施工期为枯水季节,主河道宽度为50～60米。老河道淤泥及淤砂较多,河道形状如图1。老河道表面湿润并长草,中间凸起,河床表面为细砂;在穿越点下游有已建
First, the scene conditions and options Huanxiling Xinglongtai φ529 low pressure gas pipeline through the Daling River, need to pass from below the riverbed. The design requirements of the pipeline buried depth of 1.5 meters to 2.5 meters, through the length of 540 meters, the casing is φ720 × 8, the working tube is φ529 × 8, the total weight of 145 tons, and to pour cement mortar and piling. The construction drawings for the design give the following information: The river bed has a 20-m thick runny sand layer and is a seasonal river with a flow rate of up to 4 m / s during the flood season. The two sides of the soil conditions. Based on the information given in the design, the relevant personnel conducted a site survey and learned that during the dry season of the construction period, the width of the main river channel was 50-60 meters. The old river silt and silt more, river shape shown in Figure 1. The old river surface moist and long grass, raised in the middle, the riverbed surface is fine sand; downstream of the crossing has been built