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281.
董晔 《中国地质灾害与防治学报》2001,12(1):47-50
大连小龙街边坡原始地貌陡峭,高差45.28m,由于上覆残积土及后期在建筑施工中堆积了大量的杂填土,在地表水与地下水浸泡作用下,土体失稳,产生类似泥石流性质的滑坡,毁坏原山坡走梯及下部挡墙,造成人员、住宅及财产损失。本文在大连小龙街滑坡治理工程设计时,重点考虑了滑坡的发生机理、治理工程场地施工条件、建筑美学及原有下水管线、走梯等修复工作,采用土石方清理,滑坡前缘一、二级锚拉钢筋混凝土板墙,滑坡中部花坛及走梯,滑坡后缘一、二级钢筋混凝土柱板墙,排水工程和绿化工程六部分进行施工,效果较好。可供相似城区地质灾害治理工程参考。 相似文献
282.
Stream-water samples were collected during a 4-year-period in twosmall streams, one whose catchment was ditched for forestry halfway through the sampling period and another nearby reference stream whose catchment was not ditched during this period. The main aim was to study the impact of forest ditching on stream-water quality. Whereas the artificial drainage did not change the hydrograph pattern, it had a large effect on stream hydrochemistry: the concentrations of suspended material, Mn, Ca, Mg and Al increased, theconcentrations of total organic carbon decreased, and pH increased by approximately one unit, from an average of 4.4 to 5.4. The increase in suspended material, Mn and Al concentrations is explainedby the physical mobilisation of mineral particulates/colloids from mineral soils (till) exposed on the ditch slopes beneath the peat layer, while the increase in Ca and Mg loads is explained by the release of Ca2+ and Mg2+ in exchange reactions in this same soil layer. The increase in pH and decrease in TOC concentrations after ditching are related to changes in hydrological flow paths in the catchments, and most likely to immobilisation of both hydrogen ions and humic substances in the near neutral till horizon exposed beneath the peat layer. Only the aquatic abundance of Fewas not significantly affected by the ditching. 相似文献
283.
Open cast mining of lignite leads to dumps containing highly mineralised pore waters. To predict the impact of the dump waters on the undisturbed aquifers two steps are necessary. (1) The prediction of dump water quality at times when steady state flow conditions will be established. (2) The simulation of the dump ground water migration with a model that is able to handle the complexity of the homogeneous and heterogeneous interactions of the migration process.For the investigated site Jänschwalde, which is still dewatered, a chemical mass balance was performed. The predicted alkalinity potentials exceed acidity potentials for the dump as a whole. The distribution of these parameters show high alkalinity potentials for the northern part.In order to model the migration process the transport code PCGEOFIM® [Anwenderdokumentaion, IBGW Leipzig, (in German)] was coupled with the geochemical equilibrium code PHREEQC [USGS, Water-Resources Investigations Report]. This was done to simulate redox reactions, mineral dissolution and precipitation, and cation exchange in the ground water zone. The model is verified by a column flow test. The results of the simulations show a small effect of the migrating dump waters on the quartenary aquifer with respect to acidity changes. This results from calcite buffering and cation exchange. The impact on the quartenary aquifer by sulphate is much higher. 相似文献
284.
Geochemical processes controlling silica concentrations in groundwaters of the Salado River drainage basin, Argentina 总被引:1,自引:0,他引:1
Chemical analyses of dissolved silica in the shallow groundwater of the lower part of the Salado River drainage basin indicate that silica values averaged 60 ppm. The groundwaters are oversaturated in relation to quartz, Na-plagioclase, K-feldspar, and the weathering of quartz and aluminosilicates appear to have little control on silica concentrations in solution. Groundwater is undersaturated with respect to amorphous silica present in the loessic sediments, and these sediments are specially important in the control of the groundwater composition. The sources of amorphous silica are volcanic glass shards and biogenic silica derived from plant (silicophytoliths, diatom frustules) or animal remains (sponge spicules) also present in the Pampean loess. Silicophytoliths and diatoms have also been reported in A soil horizon samples. The dissolution of amorphous silica most likely controls the high dissolved silica concentrations in groundwater. 相似文献
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In order to assess the magnitude and impact at affected mine sites of acid rock drainage (ARD), fixed-frequency sampling is often employed. This often involves manual sampling, at regular time intervals, of water and solids. It is felt that such sampling does not adequately describe the system evolution. Continuous monitoring offers a viable alternative in that it can better follow the seasonal fluctuations and high-frequency variations that characterize ARD. This paper evaluates existing continuous monitoring technology. 相似文献
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