黄土削峁填沟高填方地下水监测与分析

Groundwater monitoring and analysis of high fill foundation in loess hilly-gully region

为研究黄土削峁填沟高填方地基的地下水变化规律,对某黄土高填方工程施工期和竣工后的地下水位、孔隙水压力、盲沟水流量、地表水入渗情况进行了监测和分析.监测结果显示:填方施工抬高了局部地下水排泄基准面,工后形成稳定的排水通道后,地下水可通过沟道内敷设的盲沟排出;盲沟水流量与降雨量的季节分配具有响应关系,地下水以降水补给为主,随季节周期性变化;填土施工使饱和土中产生超静孔隙水压力,孔压增量与上部荷载增量存在线性关系,表明地基土处于稳定状态,停荷恒载,孔压逐步消散;填方区地下水埋藏深度大,压实黄土的抗渗能力强,短时地表径流和积水难以通过重力下渗方式形成对地下水的补给,但场地内发育的裂缝易成为地表水下渗通道,应引起足够重视.

In order to identify the dynamic variation regularities of groundwater of high fill foundation project in loess hilly-gullyregion, the underground water level, pore water pressure and water infiltration depth of a specific engineering are monitored duringconstruction and post-construction periods. The variation of the groundwater and its influence factors are analyzed. The monitoringresults show that the groundwater level is raised in local area during the construction periods, but when the stability drainage path isset up, the water can be discharged by blind ditches in the gully bottom. The water flow of the blind ditches is in a response relationto the seasonal distribution of rainfall and mainly supplied by atmospheric precipitation. The excess pore water pressure increasedwith the increasing thickness of earth filling and dissipated gradually after the loading stop. There is a linear relationship betweenpore pressure increment and load increment, which means a stable state. The buried depth of groundwater in filling area is deep, andthe compacted loess is of low-permeability, thus the short-term surface runoff and surface water infiltration can’t recharge thegroundwater, but the fissure in construction site may become the route for surface water infiltration, which requires more attention.