大直径管道穿越富水砂层对堤防稳定性影响分析

Analysis of the influence of large diameter pipeline crossing water-rich sand layer on embankment stability

随着地下穿管工程日益增多,地下管道施工引发的堤防安全问题屡见不鲜,研究大直径管道穿越富水砂层对堤防稳定性及变形影响十分必要。选取某引水管穿越淮北大堤工程为例,通过对顶管穿越堤防进行数值模拟,分析顶管穿越富水砂层对堤防渗透稳定和边坡抗滑稳定的影响,并在顶管施工过程中选取地层受到扰动敏感区域开展土体内部水平位移和表面沉降实时监测。结果表明:顶管穿越富水砂层堤基对堤防渗流及边坡抗滑稳定有一定影响,但总体满足规范要求;顶管施工造成迎水侧区域沉降较明显,管道两侧4~5 m范围内土体受施工扰动出现水平位移;大直径管道采用顶管方式施工对堤防安全有一定影响,施工过程中要加强对堤防的安全监测,施工前后可采取注浆、设置防渗墙等措施消除或减轻顶管施工造成的不利影响。

With the increasing number of underground pipeline projects,the safety issues of embankment caused by underground pipeline construction have become more common.It is necessary to study the influence of large diameter pipeline crossing water-rich sand layer on the stability and deformation of embankment.Taking a diversion pipe crossing Huaibei embankment project as an example,through the numerical simulation of pipe jacking crossing embankment,the influence of pipe jacking crossing water-rich sand layer on embankment seepage stability and slope anti-sliding stability is calculated.In the process of pipe jacking construction,the sensitive area of stratum disturbance is selected to carry out real-time monitoring of internal horizontal displacement and surface settlement of soil.The results showed that the pipe jacking through the water-rich sand layer has a certain influence on the seepage of the embankment and the anti-sliding stability of the slope,but it generally meets the requirements of the specification.The settlement of the water-facing side area caused by the pipe jacking construction is obvious,and the soil on both sides of the pipeline is horizontally displaced by the construction disturbance,and the influence range is within 4~5 m.The construction of large diameter pipeline by pipe jacking has a certain impact on the safety of embankment.During the construction process,the safety monitoring of embankment should be strengthened.Before and after the construction,grouting,anti-seepage wall and other measures should be taken to eliminate or reduce the adverse effects caused by pipe jacking construction.