This work focuses on an integrated approach for lake ecological status assessment, elaborated according to the requirements of the European Water Framework Directive (WFD). Data from five lowland and semi-mountain lak...This work focuses on an integrated approach for lake ecological status assessment, elaborated according to the requirements of the European Water Framework Directive (WFD). Data from five lowland and semi-mountain lakes in Bulgaria (Southeast Europe) collected from two years (2011-2012) form the basis for an integrated assessment and the definition of reference conditions. Several metrics were applied in combination, to classify lakes into five ecological status classes. Assemblages of aquatic organisms: phytoplankton, macrophytes and benthic macroinvertebrates, together with 11 supporting physico-chemical parameters were studied. The assessed unique conditions suggested that reference conditions of Bulgarian lakes have natural variability. This first baseline study illustrated specific cases within the lake types that should be assessed in details before providing standardized classification systems in compliance with the requirements of WFD.展开更多
基于江西省城门山铜矿湖底采矿特殊的工程背景,研究湖泥在堆土固结后力学性质的变化规律及影响因素。进行6组不同含水率和4组前期固结压力下非饱和重塑湖泥的直剪试验,分析不同含水率和前期固结压力对重塑湖泥抗剪强度的影响。研究结果...基于江西省城门山铜矿湖底采矿特殊的工程背景,研究湖泥在堆土固结后力学性质的变化规律及影响因素。进行6组不同含水率和4组前期固结压力下非饱和重塑湖泥的直剪试验,分析不同含水率和前期固结压力对重塑湖泥抗剪强度的影响。研究结果表明：在相同的前期固结压力下,在试验研究的含水率范围内,重塑湖泥的黏聚力和内摩擦角均随着含水率的增大而减小,且黏聚力和含水率之间基本呈负线性相关关系,拟合相关系数〉0.92,与其他含水率范围相比,重塑湖泥抗剪强度在含水率为18.62%~21.76%范围内受其变化影响更大;在相同的最终含水率下,重塑湖泥黏聚力随前期固结压力呈幂指数函数关系,而内摩擦角的变化由于存在突变,并无一定的变化规律;不同初始含水率的重塑湖泥在300 k Pa和400 k Pa固结压力下固结96 h后,最终含水率都接近于塑限（18.5%）,反算得到最佳湖泥填土高度为14 m。展开更多
文摘This work focuses on an integrated approach for lake ecological status assessment, elaborated according to the requirements of the European Water Framework Directive (WFD). Data from five lowland and semi-mountain lakes in Bulgaria (Southeast Europe) collected from two years (2011-2012) form the basis for an integrated assessment and the definition of reference conditions. Several metrics were applied in combination, to classify lakes into five ecological status classes. Assemblages of aquatic organisms: phytoplankton, macrophytes and benthic macroinvertebrates, together with 11 supporting physico-chemical parameters were studied. The assessed unique conditions suggested that reference conditions of Bulgarian lakes have natural variability. This first baseline study illustrated specific cases within the lake types that should be assessed in details before providing standardized classification systems in compliance with the requirements of WFD.
文摘基于江西省城门山铜矿湖底采矿特殊的工程背景,研究湖泥在堆土固结后力学性质的变化规律及影响因素。进行6组不同含水率和4组前期固结压力下非饱和重塑湖泥的直剪试验,分析不同含水率和前期固结压力对重塑湖泥抗剪强度的影响。研究结果表明：在相同的前期固结压力下,在试验研究的含水率范围内,重塑湖泥的黏聚力和内摩擦角均随着含水率的增大而减小,且黏聚力和含水率之间基本呈负线性相关关系,拟合相关系数〉0.92,与其他含水率范围相比,重塑湖泥抗剪强度在含水率为18.62%~21.76%范围内受其变化影响更大;在相同的最终含水率下,重塑湖泥黏聚力随前期固结压力呈幂指数函数关系,而内摩擦角的变化由于存在突变,并无一定的变化规律;不同初始含水率的重塑湖泥在300 k Pa和400 k Pa固结压力下固结96 h后,最终含水率都接近于塑限（18.5%）,反算得到最佳湖泥填土高度为14 m。
