同心式射流泵在深层井点降水中的应用   总被引：1，自引：1，他引：1  

卜长根  孙孝庆  刘国平 《水文地质工程地质》2002,29(1):52-53,67

本文比较了几种深层干扰降水的特点，就国内深层降水设备存在的问题，有针对地研制了同心式射流泵井点降水系统，该系统利用喷射泵真空和排出口压力提升地下水，其降水深度大，集水效果好，出水量稳定，速度较快，设备结构简单可靠，解决了深大基坑砂、粘土地层中干扰降水的问题。  相似文献   

粤北层控铅-锌-硫矿床成矿机理及控矿地质因素     

陈元琰 《矿床地质》1994,13(2):118-125

粤北层控铅－锌－硫矿床产于晚古生代沉积盆地边缘的碳酸盐岩中，是沉积盆地自身发展演化中的产物。含矿热液主要是沉积盆地下部的泥质岩层在后生演化阶段发生压挤脱水作用形成的，金属硫化物是从盆地中心向上运移的含矿热液与碳酸盐岩中富含Ｈ＿２Ｓ气体的地下水混合而结晶沉淀的，成矿主要受沉积盆地建造、盆地边缘或古岛古隆起、构造、沉积相和白云岩化五个因素控制。  相似文献   

Dewatering and extensional deformation of the Shikoku Basin hemipelagic sediments in the Nankai Trough     

Cynthia J. Bray  Daniel E. Karig 《Pure and Applied Geophysics》1988,128(3-4):725-747

The Shikoku Basin hemipelagic sequence, which underlies the Nankai Trough wedge, S.W. Japan, thins by 50% between the outer edge of the trench wedge and DSDP Site 582, 14 km arcward. A sedimentation model, which incorporates changes in sedimentation rates with time and with distance from the trench wedge toe, indicates that 57% of the total thinning occurs as a result of temporally varying sedimentation rates and a time transgressive facies boundary between the trench wedge turbidites and the underlying hemipelagites. Burial-induced consolidation beneath the wedgeshaped turbiditic overburden, accounts for the remaining 43% of arcward thinning within the hemipelagic unit. Rapid dewatering, modeled as one-dimensional consolidation suggests that the excess pore water pressures are quite low during this progressive dewatering. Thus, high pore water pressures should not be assumed to occur universally in convergent margin settings. Normal faults and vein structures in the hemipelagites suggest near-horizontal extension in addition to vertical consolidation. The estimates of excess pore water pressures together with fault geometries and horizontal extensional strains, determined from the geometry of the subducting oceanic plate, can be used to constrain the stress conditions at failure. The expulsion of hot water from the rapidly dewatering sediments in the Nankai Trough may help to explain anomalously high heat flow in the central part of the trough.  相似文献   

Subduction-channel model of prism accretion,melange formation,sediment subduction,and subduction erosion at convergent plate margins: 2. Implications and discussion     

Mark Cloos  Ronald L. Shreve 《Pure and Applied Geophysics》1988,128(3-4):501-545

The subduction-channel model predicts five geologically and geophysically distinctive types of convergent plate margin. They differ primarily in the proportions of incoming sediment and upflowing melange offscraped and underplated near the toe of the overriding block. The model predicts complex patterns of uplift or subsidence of the forearc region due to differential underplating or subduction erosion and to initiation or cessation of melange upflow. It shows how subduction speed, sediment input, and pressure gradient along the channel govern the general distribution and magnitude of subduction-zone earthquakes. It can predict the upward trajectories of exotic blueschist or serpentinized peridotite blocks that become entrained in the upwelling melange; and it suggests mechanisms by which much larger tracts of coherent blueschist can be raised to shallower levels. It predicts characteristic structural and metamorphic histories for geologic units accreted during steady-state subduction, showing for example, that offscraped materials undergo subhorizontally-directed compression during final dewatering and accretion, whereas underplated ones undergo large simple shear. It gives the maximum depths reached by upwelled melange, which bear significantly on the metamorphic changes observed in them. It predicts large-scale melange diapirism in certain rare cases, in which the normally adverse pressure gradient is reversed in a short reach of the channel, as at Barbados Island. Finally, it explains why pelagic sediments are seldom found in accretionary complexes and gives insight into the factors controlling what portion of the incoming sediment, and the¹⁰Be and other tracers it carries, will reach the region of volcanic-arc magmagenesis.  相似文献   

杂填土含水层大型深基坑的降水方法     

郭加苜 《福建地质》1996,15(2):111-116

杂填土含水层大型深基坑降水，应根据场地的施工环境，采用人工挖掘辐射降水井、引水入基坑的降水方法，并将排水系统修筑在连梁上面，这样可取得良好的降水效果。  相似文献   

邢台煤矿放水试验中的水质变化特征及水文地质条件分析   总被引：1，自引：0，他引：1  

顾敏 《煤田地质与勘探》1997,(Z1)

论述了邢台煤矿放水试验中的水质变化特征，并根据地球化学原理，利用指标组合、水质图像分析方法，把试验区水质分为典型奥灰水和大青水，大青水又分为三种情形，而且计算出各混合水中奥灰水的比例，从而得出该矿三个水文地质单元的富水地段及其补给源和补给强度。  相似文献   

深基坑开挖降水及钢板桩围护工程     

史炳奇  王国英 《地质与勘探》1995,31(5):57-61

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辐射井降水技术在大面积基坑工程中的应用          下载免费PDF全文

张治晖  刘德林  兰晓林 《探矿工程》2008,35(11):53-55

辐射井降水技术适用于各种地层,单井控制降水面积大,对疏干含水层有特效,与其它工序干扰小,占地面积少,管理方便,是大面积基坑降水的有效方法。通过中国电影博物馆基坑降水实例,介绍在大面积基坑工程中辐射井降水技术的设计、施工及降水效果。  相似文献   

Groundwater control for construction purposes: a case study from Kuwait   总被引：1，自引：0，他引：1  

Fathi M. Shaqour  Syed E. Hasan 《Environmental Geology》2008,53(8):1603-1612

One of the major rehabilitation projects in Kuwait during the 1990s was improvement of the wastewater treatment plant at Jahra, a town 30 km north of Kuwait City. The project incorporates construction of a pumping station to collect the sewage via a network of sewer lines throughout the city. Groundwater occurs 4 m below the ground surface and construction specifications required lowering the groundwater table by 16 m to the foundation grade, 20 m below the ground surface. Open excavation with four stage well point system of dewatering was selected to ensure dry foundation conditions; but the system failed to lower the groundwater table down to the desired depth. Review of site investigation records and recalculation of field hydraulic conductivity resulted in design changes, augmenting the well point system with a number of deep wells and sumps to lower the water table down to the foundation grade. The paper discusses subsurface conditions and presents an analysis of the cause of failure of the well point system. The actual hydraulic conductivity proved to be several folds higher than the calculated one that was determined using Hazen’s formula. It was found that use of Hazen’s formula led to serious underestimation of field hydraulic conductivity. It is advised not to use such formulas without thorough investigation and proper interpretation of borehole data.  相似文献   

Laboratory Investigations for Dewatering of Golden Horn Dredged Sludge with Geotextile Tubes     

Saadet A. Berilgen  Begüm Turan Bulut 《Marine Georesources & Geotechnology》2016,34(7):638-647

In this study, an effective means of dewatering the dredged material obtained from the sea-bottom in Istanbul is investigated through the use of additives and geotextile tubes (also known as geotubes, geotextile containers, and geotextile bags). Rapid dewatering test and geotube dewatering test are laboratory approaches, where the types and amounts of anionic and cationic additives for dewatering efficiency of dredged sludge can quickly and economically be examined. In this study, a best dosage amount of 1.5 kg/tonne was used as flocculant solution preparation with distilled water. After this process, twelve homogeneous sludge-polymer admixtures were prepared by adding 0.1, 0.5, and 1.0% polymers (anionic and cationic) by weight of the dredged material in rapid dewatering tests and another twelve homogeneous sludge-polymer admixtures were prepared by adding 0.1, 0.25, and 0.50% polymers (anionic and cationic) by weight of the dredged material in geotube dewatering tests. The results indicated that Golden Horn dredged sludge could be successfully dewatered and retained by geotextile tubes. The use of chemical cationic polymers is recommended with Golden Horn dredged sludge rather than the anionic polymers. Results also showed that use of flocculants can significantly increase the retention capacity of geotubes.  相似文献