西气东输二线遂川江顶管穿越施工监测

Monitoring of pipe jacking crossing Suichuan River in the 2nd West-to-East Gas Pipeline

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。

This paper describes the construction technology and principle of pipe jacking in crossing Suichuan River in the 2nd West-to-East Gas Pipeline.The optimal surface settlement monitoring program is selected in accordance with actual geological conditions.Monitoring measurement values indicate that the mass displacement change of surface soil after pipe jacking is related to the distance between pipe pusher and monitoring point,and the monitoring point near the axis is much larger than surrounding monitoring points in the settlement change.In four stages of displacement change,the displacement in the second stage is largest.After the pipe pusher passes through the monitoring point,stress relaxation causes reduction of soil pressure,which results in rapid settlement of the ground.In the pipe jacking construction,overlying soils is first uplifted and then settled to gradually reach a fixed value under normal work condition.Settling volume caused by the jacking in different stages is calculated and the calculation data is in a small difference to measured data,which shows that the monitoring data can be taken as the basis in evaluating pipe jacking construction safety conditions.