在人类工程活动和气候变暖的双重作用下,多年冻土区的道路路基普遍产生以路基下沉为主的病害.多年冻土地区的路基沉降涉及多个物理力学过程:未冻土的蠕变,冻土上限下降所产生的融沉,由于多年冻土层升温而产生的高温冻土的蠕变,以及活动层中冻融循环改变了土的工程性质而导致的附加沉降变形.为了进一步探索各个物理力学过程对总沉降量贡献,针对不同地质地貌条件下的青藏公路路基段,布设了路基分层变形沉降杆,通过野外观测资料分析了引起路基沉降的物理力学过程,即变形源.这对于揭示路基变形机理以及多年冻土区的路基病害防治都具有重要意义.
Under the influence of both engineering activities and global warming, settlement is regarded as a heavy embankment disease in permafrost regions, which may result from many physical and mechanical processes, i. e. , creep of unfrozen layers, thawing settlement due to the degradation (thawing) of the permafrost underneath, creep of warm frozen layers, freeze-thaw cycling of the active layer. In order to investigate the contribution of each physical and mechanical process to embank-ment settlement, settlement measuring devices were embedded in many sections with different geological and geomorphic conditions along the Qinghai-Tibet Highway. Through field observation, the physical and mechanical processes in embankment settlement, regarded as deformation sources, were analyzed. The result will have a great signifi- cance for revealing the settlement mechanisms of embankment and controlling the embankment diseases.