大庆市地下水开采及环境地质问题探讨

大庆市主城区长期过量开采承压水,致使地下水水位持续下降,形成地下水降落漏斗.依据调查资料,分析了大庆市主要的环境地质问题.面对地下水降落漏斗、地面沉降、饮水型地方病、土地盐碱化、湖泡污染等环境地质问题,提出相应的保护措施.     

海底管线区浅表层土孔压静力触探参数特征及应用

利用东海陆架海底输油管道路由调查获得的孔压静力触探数据和钻探资料等,采用统计分析的方法,对管道路由区5 m以浅土体的孔压静力触探曲线特征、土的分类方法鉴别作了探讨,结果表明:研究区5 m以浅黏性土的锥尖阻力(qc),侧摩阻力(fs)值较小,且随深度呈线性增加,粉质土的qc,fs值增大,但随深度线性增加规律不明显,砂类土的qc值急剧增大,但fs值变化不大;Robertson法和Eslami-Fellenius法两种土类划分方法均适用于研究区浅表层软土的土类划分,但Robertson法在判别粉质土时受到一定限制,Eslami-Fellenius法判别较为准确,应用简单。本研究可为我国在海底管线工程路由勘察中直接利用孔压静力触探(CPTU)参数划分土层和判别土类作铺垫。     

原位贯入装置标定罐模型试验研究与发展

为明确标定罐模型试验在室内模拟原位测试技术领域中的研究现状,根据国内外大量文献中相关标定罐模型试验的报道,对现今世界上已有的大型标定罐进行了总结,并对比分析了各个标定罐的优缺点以及标定罐的改进历程。介绍了国内外使用最为广泛的两种标定罐体系的相关研究内容,论述了影响标定罐模型试验的相关参数以及影响因素,并归纳了标定罐试验的应用研究结果。分析结果表明,标定罐模型试验在原位测试技术的应用研究具有很好的应用前景,且集边界条件控制、应力状态控制、土样控制等各种特点于一身;通过标定罐试验进行相关的土体参数的推算与验算,与之相应的原位试验进行对比,分析了不同土层的现场经验公式,可为原位试验的评价与分析提供依据。但是,标定罐试验的相关研究还需进一步的加强与扩展,目前主要是砂质土的相关研究,对于黏性土和特殊土尚缺少相关研究;原位测试参数方面也应加强对侧摩阻力、孔隙水压力等相关参数的试验研究。     

浙江晚泥盆世五通组中的楔叶类(Sphenophyllales)化石

本文描述了产自浙江长兴泗安五通组中的几种楔叶类化石Eviostachya hoegii(Stockmans)、Arch-aeocalamites sp.、Hamatophyton verticillatum Gu et Zhi、Sphenophyllum pseudotenerrimum(Sze)和Sphenophyllostachys sp.等.特别是Eviostachya hoegii的发现,为浙江晚泥盆世地层进行国际性对比,提供了新的依据.     

Managing groundwater rise: Experimental results and modelling of water pumping from a quarry lake in Milan urban area (Italy)

An innovative approach to solve the problem of lowering water table was carried out in a quarry lake south of the city of Milan (northern Italy): the project, based upon pumping out water at a rate of 1,000 L/s can be considered a strategic medium to long-term solution to hinder the rise of groundwater level interfering with underground structures (foundation, construction, subway) in urban areas. The basic idea is to pump a high groundwater rate as close as possible to the stagnation point of the piezometric depression located in the city. After a pilot-test was carried out in November 1998, experimental activities started in July 2001 and lasted one year; water withdrawal was discharged into artificial channels used in agricultural practice. Maximum drawdowns measured in the quarry lake by the monitoring network resulted in more than 5 m, and a significant drawdown was registered up to 1.5 km of distance from the quarry in the important historical site of Chiaravalle Abbey, threatened by groundwater rise. The results of this pumping activity confirm the importance of the project, its lower cost compared with traditional solutions (such as drainage by wells) and remarkable effects on the improvement of surface water quality. A groundwater model was implemented to evaluate further scenarios of discharge rate and pumping location, too.     

A New Computer Program for Pile Capacity Prediction using CPT Data

An interactive computer program “GLAMCPT” is developed for application in soil profiling and prediction of pile load capacity using cone penetration test (CPT) and laboratory soil test results. GLAMCPT calculates pile capacity according to 10 selected methods from European design codes, refereed international publications and recommendations of professional institutions. To demonstrate the capabilities of the program, a database of comprehensive ground investigation and full-scale pile tests in sand, at a Belgian site, is analysed using GLAMCPT. The database comprises 11 static tests and 12 dynamic tests on piles of different construction techniques, including driven pre-cast concrete piles and screwed cast in-situ piles, installed using 5 different procedures. Prior to pile installation, CPTs were carried out at each proposed pile location. Comparison of GLAMCPT predictions with the observed pile capacities reveals that the most accurate of the existing methods yields an average, μ, of predicted to observed pile head capacity [P_uh(p)/P_uh(m)] equal to 0.94. The most consistent method produces a coeffcient of variation (COV) of [P_uh(p)/P_uh(m)] equal to 0.1 and ranking index (RI) of 0.08. Parametric studies have been carried out using GLAMCPT to formulate an improved predictive method, which yielded: μ = 0.99, COV = 0.07 and RI = 0.04.     

烟台市海水入侵程度及影响因素探讨

介绍了烟台市开发区夹河地区20年来海水入侵的现状及过程。基于区内4个监测井点的长期观测资料,讨论了影响海水入侵程度的主要因素,认为烟台市海水入侵程度与区内地下水动态关联密切。在海侵区内,地下水被海水浸染的程度主要受地下水位降深控制,地下水降落漏斗范围内海水对地下水浸染程度随水位下降逐年加剧,而漏斗区外地下水质则多年保持相对稳定。     

METEOROLOGICAL CONDITIONS DURING SLUSH-FLOW RELEASE AND THEIR GEOMORPHOLOGICAL IMPACT IN NORTHWESTERN ICELAND: A CASE STUDY FROM THE BÍLDUDALUR VALLEY

ABSTRACT. This paper examines triggering factors and geomorphic significance of slush flows in the Bíldudalur valley, northwestern Iceland. The area is prone to release slush flows from two confined gullies, and at least ten flows have been reported since the beginning of the twentieth century. Despite their short path (600 m) and their moderate magnitude (from 6000 to 8000 m³), slush flows in the Bíldudalur valley represent a serious threat for the local community that is situated within the runout and deposition zones. With the help of meteorological data, the release of known slush flows is examined, highlighting the role of heavy rainfall and rapid snow-melt during winter cyclonic activity. The geomorphological impact of slush flows is assessed through the characteristics of the landforms produced during the 1997 and 1998 slush-flow events. It appears that the most obvious characteristics of slush flows in the Bíldudalur valley are the entrainment and deposition of debris, spatially differentiated. Chaotic sedimentation occurs chiefly in the middle part of a clearly concave cone, even if the flows continue beyond the cone.     

基于锥形模型的空间方向查询研究

分析了基于锥形模型进行空间方向查询的原理,提出应结合不同实际应用领域和针对不同的空间数据特征选择适当的空间方向关系形式化描述模型的思想。按照这种思想,针对全国各省1∶25万县市级行政区划数据,设计并实现了基于八方向锥形模型的空间方向查询,取得了比较好的检索效果。     

Geologic heterogeneity and a comparison of two geostatistical models: Sequential Gaussian and transition probability-based geostatistical simulation

A covariance-based model-fitting approach is often considered valid to represent field spatial variability of hydraulic properties. This study examines the representation of geologic heterogeneity in two types of geostatistical models under the same mean and spatial covariance structure, and subsequently its effect on the hydraulic response to a pumping test based on 3D high-resolution numerical simulation and field data. Two geostatistical simulation methods, sequential Gaussian simulation (SGS) and transition probability indicator simulation (TPROGS) were applied to create conditional realizations of alluvial fan aquifer systems in the Lawrence Livermore National Laboratory (LLNL) area. The simulated K fields were then used in a numerical groundwater flow model to simulate a pumping test performed at the LLNL site. Spatial connectivity measures of high-K materials (channel facies) captured connectivity characteristics of each geostatistical model and revealed that the TPROGS model created an aquifer (channel) network having greater lateral connectivity. SGS realizations neglected important geologic structures associated with channel and overbank (levee) facies, even though the covariance model used to create these realizations provided excellent fits to sample covariances computed from exhaustive samplings of TPROGS realizations. Observed drawdown response in monitoring wells during a pumping test and its numerical simulation shows that in an aquifer system with strongly connected network of high-K materials, the Gaussian approach could not reproduce a similar behavior in simulated drawdown response found in TPROGS case. Overall, the simulated drawdown responses demonstrate significant disagreement between TPROGS and SGS realizations. This study showed that important geologic characteristics may not be captured by a spatial covariance model, even if that model is exhaustively determined and closely fits the exponential function.