A study was conducted in eight districts, viz., Faridkot, Moga, Ferozepur, Muktsar, Bathinda, Mansa, Barnala and Sangrur in south-western part of the Punjab, India to characterize aquifer strata by preparing a fence d...A study was conducted in eight districts, viz., Faridkot, Moga, Ferozepur, Muktsar, Bathinda, Mansa, Barnala and Sangrur in south-western part of the Punjab, India to characterize aquifer strata by preparing a fence diagram depicting sub-surface strata and distribution of groundwater quality. The sub-surface lithology drilled upto a depth of 60 m reveal the presence of top most layer of impervious strata comprising of clay upto the depth of 2 m to 5 m which impedes the percolation of surface runoff into the soil leading to surface flooding and water logging even in areas having saturated zone beyond the depth of 5 m. Thick pervious strata of 45 m to 50 m thickness is encountered in central and south-sentral part of the study area comprising of Bathinda, Muktsar and Mansa districts which at certain places are separated by one or two thin layers of impervious or semi-pervious strata comprising of clay and sand occasionally associated with ＂kankar＂ of thickness ranging between 2 m to 5 m. The northern, western and eastern parts, however, exhibit three to four layered pervious zones ranging in thickness from 5 m to 25 m separated by thin layers of impervious and semi pervious strata. The groundwater quality in about 6% of the study area in eight districts is fit, 18% is marginal and 76% is unfit for irrigation purpose.展开更多
以兰州市轨道交通1号线穿河段泥水平衡盾构隧道为工程背景,针对砂卵石强透水地层盾构隧道开挖面稳定性问题,应用FLAC 3D建模分析渗流作用下隧道开挖面的极限支护压力。结果表明:隧道开挖后围岩渗流场发生改变,产生水压力差,造成地下水...以兰州市轨道交通1号线穿河段泥水平衡盾构隧道为工程背景,针对砂卵石强透水地层盾构隧道开挖面稳定性问题,应用FLAC 3D建模分析渗流作用下隧道开挖面的极限支护压力。结果表明:隧道开挖后围岩渗流场发生改变,产生水压力差,造成地下水沿洞周渗出,孔隙水压力等值线呈漏斗状分布;渗流作用下开挖面极限支护压力为107 k Pa,岸堤经泥水盾构下穿后沉降量较小。最大沉降现场监测值与数值计算值误差为11.1%,表明计算模型合理,计算结果可靠。展开更多
文摘A study was conducted in eight districts, viz., Faridkot, Moga, Ferozepur, Muktsar, Bathinda, Mansa, Barnala and Sangrur in south-western part of the Punjab, India to characterize aquifer strata by preparing a fence diagram depicting sub-surface strata and distribution of groundwater quality. The sub-surface lithology drilled upto a depth of 60 m reveal the presence of top most layer of impervious strata comprising of clay upto the depth of 2 m to 5 m which impedes the percolation of surface runoff into the soil leading to surface flooding and water logging even in areas having saturated zone beyond the depth of 5 m. Thick pervious strata of 45 m to 50 m thickness is encountered in central and south-sentral part of the study area comprising of Bathinda, Muktsar and Mansa districts which at certain places are separated by one or two thin layers of impervious or semi-pervious strata comprising of clay and sand occasionally associated with ＂kankar＂ of thickness ranging between 2 m to 5 m. The northern, western and eastern parts, however, exhibit three to four layered pervious zones ranging in thickness from 5 m to 25 m separated by thin layers of impervious and semi pervious strata. The groundwater quality in about 6% of the study area in eight districts is fit, 18% is marginal and 76% is unfit for irrigation purpose.
文摘为研究强透水地层水平帷幕作用下基坑渗流特性,基于Darcy渗流理论,建立了水平封底帷幕作用下基坑渗流计算模型,推导出基坑内涌水量及帷幕底部水压的理论解,并通过室内渗流试验,验证了理论计算方法的可靠性.分析了渗透系数比、帷幕厚度以及帷幕与基坑底部的距离对基坑渗流的影响.研究结果表明:渗透系数比对渗流的影响起主导作用,当渗流系数比为0.01时,涌水量仅为不设帷幕的10%;帷幕厚度对渗流具有一定影响,而帷幕位置对渗流几乎没有影响.建议强透水地层基坑水平帷幕渗透系数比不宜高于0.01,厚度不宜小于4 m.
文摘以兰州市轨道交通1号线穿河段泥水平衡盾构隧道为工程背景,针对砂卵石强透水地层盾构隧道开挖面稳定性问题,应用FLAC 3D建模分析渗流作用下隧道开挖面的极限支护压力。结果表明:隧道开挖后围岩渗流场发生改变,产生水压力差,造成地下水沿洞周渗出,孔隙水压力等值线呈漏斗状分布;渗流作用下开挖面极限支护压力为107 k Pa,岸堤经泥水盾构下穿后沉降量较小。最大沉降现场监测值与数值计算值误差为11.1%,表明计算模型合理,计算结果可靠。
