排序方式： 共有67条查询结果，搜索用时 15 毫秒
61.
62.
Traditional methods for studying surface water and groundwater interactions have usually been limited to point measurements, such as geochemical sampling and seepage measurement. A new methodology is presented for quantifying groundwater discharge to a river, by using river surface temperature data obtained from airborne thermal infrared remote sensing technology. The Hot Spot Analysis toolkit in ArcGIS was used to calculate the percentage of groundwater discharge to a river relative to the total flow of the river. This methodology was evaluated in the midstream of the Heihe River in the arid and semiarid northwest China. The results show that the percentage of groundwater discharge relative to the total streamflow was as high as 28%, which is in good agreement with the results from previous geochemical studies. The data analysis methodology used in this study is based on the assumption that the river water is fully mixed except in the areas of extremely low flow velocity, which could lead to underestimation of the amount of groundwater discharge. Despite this limitation, this remote sensing‐based approach provides an efficient means of quantifying the surface water and groundwater interactions on a regional scale. 相似文献
63.
64.
65.
66.
Wenjing Qu Hailong Li Chaoyue Wang Chunmiao Zheng Xuejing Wang Yan Zhang 《Ground water》2020,58(4):550-559
Studies investigating the effects of inland recharge on coastal groundwater dynamics were carried out typically in unconfined aquifers, with few in confined aquifers. This study focused on the groundwater dynamics in confined aquifers with seasonally sinusoidally fluctuated inland groundwater head and constant sea level by numerical simulations. It is known that the mixing zone (MZ) of saltwater wedge in response to the seasonal oscillations of inland groundwater head swings around the steady-state MZ. However, our simulation results indicate that even the most landward freshwater-saltwater interface over a year is seaward from the steady-state location when the hydraulic conductivity K is ≤10−4 m/s under certain boundary conditions with given parameter values. That is, seasonal oscillations of inland groundwater head may reduce seawater intrusion in confined coastal aquifers when K ≤ 10−4 m/s. Sensitivity analysis indicates that for aquifers of K ≤ 10−4 m/s, the larger the inland head fluctuation amplitude is, the less the seawater intrudes. This is probably due to the reason that the seawater intrusion time decreases with the increase of fluctuation amplitude when K ≤ 10−4 m/s. Numerical simulations demonstrate that seasonal inland groundwater head oscillations promote the annual averaged recirculated seawater discharge across the seaward boundary. 相似文献
67.
厦门海底隧道围岩稳定动态反演分析 总被引：4，自引：2，他引：2
位移反分析法作为联系理论与实际的桥梁,为工程决策、设计与施工提供了切实可行和有效的方法。为解决海底隧道勘察、设计与施工技术难题,减小设计与施工风险,通过对先行服务隧道建立动态反演预测模型,及时对主隧道前方地质情况进行超前预报,并对围岩稳定性进行准确判断,根据反馈信息,对主洞前方设计与施工方案进行科学合理地组织,必要情况下须对原设计的隧道支护参数与施工方法作调整和修正,做到动态信息化设计与施工,确保海底隧道顺利穿越。 相似文献