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介绍了西气东输二线遂川江顶管施工工艺及原理,结合实际地质状况,选定了最佳的地表沉降监测方案。监控量测数值表明:顶管穿越后地表土体位移的变化与顶管机和监测点之间的距离有关,且接近轴线处监测点的沉降变化明显大于周围测点。在位移产生变化的4个阶段中,第2阶段的位移量最大,而在顶管机通过监测点后,应力松弛引起土压下降,从而导致地面迅速沉降。在顶管施工过程中,上覆土体通常都是先隆起后沉降,逐渐趋于定值。对顶进过程中不同时期引起的沉降量进行计算,计算结果与实测数据相差微小,表明监测数据可以作为评价顶管施工安全状况的依据。
The construction technology and principle of the Suichuan main pipe of the second West-East Gas Pipeline Project are introduced. According to the actual geological conditions, the best monitoring plan of surface subsidence is selected. The monitoring measurements show that the displacement of the soil surface after jacking pipe jacking is related to the distance between the pipe jacking machine and the monitoring point, and the settlement change at the monitoring point close to the axis is obviously larger than that of the surrounding measuring point. In the four stages of displacement change, the displacement of the second stage is the largest. After the pipe jacking machine passes the monitoring point, the earth pressure drops due to the stress relaxation, resulting in rapid settlement of the ground. During the construction of pipe jacking, the overlying soils usually settle first and then settle gradually. The subsidence caused by different stages during the jacking process is calculated. The calculated result is slightly different from the measured data, which shows that the monitoring data can be used as the basis to evaluate the safety of the jacking construction.