A MICROCOMPUTER PROGRAM FOR INTERPRETING TIME-LAG PERMEABILITY TESTS

Abstract. Single-well tests based on the rate of water-level recovery after raising or lowering the water level in a well have long been used as a quirk and simple method of obtaining order-of-magnitude estimates of hydraulic conductivity. The BASICS program presented allows for the rapid interpretation of these tests for most field situations.     

AUTOMATED ANALYSIS OF PUMPING TESTS IN UNCONFINED AQUIFERS OF SEMI-INFINITE THICKNESS

Abstract A procedure is described for automated fitting of test data for pumping from an unconfined aquifer of semi-infinite thickness. The fitting is achieved by sensitivity analysis and the least-squares method. The early time data are fitted to the Streltsova (1974) model and the late time data are matched to the Dagan (1967) model. These solutions are useful where the aquifer thickness is extensive and unknown. Data from a test in the Indus Basin, Pakistan, was analyzed to test this procedure.     

PUMPING TESTS ON OPEN WELLS IN PALAR ALLUVIUM,NEAR MADRAS CITY,INDIA AN APPLICATION OF THE PAPADOPULOS-COOPER METHOD

Abstract

The non-equilibrium formula of Theis has hitherto been found to be inadequate to analyse drawdown data from open wells, due to the influence of effects of well-storage on early drawdown data. Recently, a reliable type-curve method was proposed by Papadopulos and Cooper to analyse drawdowns in wells of large diameter. In order to study its practical validity, the Papadopulos-Cooper method was applied to drawdown data from six open wells, tapping the alluvial sands of the river Palar, near Madras city, India. The study has indicated that the method has considerable practical utility in analysing drawdown data from large diameter open wells. Besides, the method also offers an easy way of computing the duration over which the effects of well-storage are likely to influence drawdown data, in terms of aquifer transmissibility and well-radius. If a rough idea of aquifer trans-missibility is available from existing data, then, such a computation, to determine the duration over which wellstorage affects drawdown, could be initially made to advantage, so that proper judgement could be exercised in using other conventional methods of analysis, such as that of Jacob or that of Theis. (Key Words: Pumping tests; Open wells; Papadopulos-Cooper method.)     

从约束结构试验中提取自由-自由模态的一种通用的矩阵摄动法

根据作者提出的一种通用的矩阵摄动法,研究了从约束结构的地面共振试验结果中,提出自由－自由结构的模态参数的具体方法和步骤。几个不同的计算实例充分验证了本文方法合理可靠,具有足够的精度。     

EFFECT OF INFILLS ON THE GLOBAL BEHAVIOUR OF R/C FRAMES: ENERGY CONSIDERATIONS FROM PSEUDODYNAMIC TESTS

A series of pseudo-dynamic tests were conducted on a full-scale four-storey reinforced concrete building designed according to Eurocodes 2 and 8. The building was 10 m long, 10 m wide, and 12⋅5 m high. It was designed as a ductility class ‘High’ structure, for typical live loads and for a peak ground acceleration of 0⋅3 g and medium soil conditions. A first test was conducted on the bare frame. The project was carried out within the framework of the European Association of Structural Mechanics Laboratories (EASML), and was designed to assess the adequacy of the damage indicators to be used in the calibration of Eurocode 8. The pseudodynamic test was conducted by using an artificially generated earth-quake derived from a real earthquake (Friuli, 1976), with nominal acceleration 50 per cent larger than the value adopted in design. The structure performed as expected. The pattern of the measured rotations was that of a weak-beam, strong-column mechanism. The fundamental frequency of the structure after the test was found to be half of the initial value, but the damage was limited and uniformly distributed. A second experimental programme was conducted as part of the work of the Network Prenormative Research in support of Eurocode 8, to study the influence of masonry infill panels on the global behaviour of the frame. Two pseudodynamic tests were conducted, with different infill patterns. A test was performed by infilling the two external frames with hollow brick masonry in all four storeys (uniform infill distribution). The test was then repeated on the structure without infills at the first storey, to create a soft-storey effect. The input signal was the same as in the tests on the bare frame. The purpose of the tests was to study the effects of the different layouts of infills, as well as to calibrate the computer models for the infills to be used in parametric analyses. In this paper the test results are presented and the performances of the structure with different infill configurations are compared. The global behaviour of the structure is compared with the predictions which could have been made with simplified approaches. In particular, single degree of freedom energy concepts are used to verify if the differences in the global behaviour could have been predicted. The differences in the single degree of freedom energy demands with respect to the bare frame may be used as a means of accounting for the presence of irregular distributions of non-structural infills in the simplified design of the frame.     

He4光泵梯度磁强计

一、概述 He~4光泵梯度磁强计是一种精密测量地球磁场总强度的水平梯度和垂直梯度的仪器。它由两套相同的光泵系统组成,并测其差频。 本仪器是用亚稳态He~4(正氦)2~3S_1能级的塞曼子能级间的共振跃迁即“光泵”来实现的。He~4塞曼子能级间的宽度正比于地磁场强度。对于He~42~3S_1态mj=+1能级到mj=0能级间有     

NUMERICAL METHOD OF PUMPING TEST ANALYSIS USING MICROCOMPUTERS

Abstract. This paper describes how a numerical method of pumping test analysis, which has proved to be useful in many practical situations, can be run on microcomputers. Full details of a program in BASIC and a test problem are provided. The need to perform all the calculations to a sufficient accuracy is stressed, and the choice of suitable mesh spacings and time steps is discussed.     

孔隙介质声学理论中的动态渗透率

解释了Johnson动态渗透率k(ω)的概念,指出k(ω)包含了Biot理论中质量耦合系数和粘滞修正系数的意义,对k(ω)与Biot理论中相应表达式kB(ω)进行了比较,当结构因子β≈64α∞/m时k(ω)与kB(ω)的差异很小.计算表明,当声源频率接近临界频率时声测井波形中导波的衰减随质量耦合系数增大而减小.     

孔隙介质声学理论中的动态渗透率

解释了Johnson动态渗透率k(ω)的概念，指出k(ω)包含了Biot理论中质量耦合系数和粘滞修正系数的意义，对k(ω)与Biot理论中相应表达式k_B(ω)进行了比较，当结构因子β≈64α_∞/m时k(ω)与k_B(ω)的差异很小.计算表明，当声源频率接近临界频率时声测井波形中导波的衰减随质量耦合系数增大而减小.     

含裂面岩石渗透率的实验研究

本文在实验室中采用定常压力差法在围压10—20MPP、注水压力为2.5—12.SMPS条件下对新丰江水库区花岗岩及刘家峡水库区变质岩进行了渗透实验,观测到了岩石渗透率随围压、注水压力及时间变化的结果,并且得到了渗透率随时间衰减的经验关系l。(t)=k。XEXP(一、t)。实验结果表明:完整岩石、自然裂而中含填充物岩石、自然裂面岩石的渗透率依次增大两个数量级。在实验中,恒定注水压力时渗透率明显地随着围压的增大而减小,当国压变化发生循环时,渗透率产生了不可恢复的减小;当恒定因压时,渗透率随着注水压力的变化取决于流体水对裂面的冲刷、溶解及沉淀堵塞作用而不可预测。最后根据该实验结果讨论了水库地震中水沿断裂系统渗透过程中渗透水的前锋形成高孔隙压力而触发地震的机制。     

基于SfM方法的高密度点云数据生成及精度分析

地形数据的质量(精度和分辨率)影响着地球科学的研究水平。Li DAR测量是目前获取高分辨率地形数据的有效技术方法之一,但是其高昂的测量成本和相对复杂的后期数据处理限制了Li DAR技术的大众化应用。近年来,一种被称为Sf M(Structure from Motion)的适合大众化使用的新的高精度3维地形数据获取技术开始引起人们的注意。这种新型数字摄影测量技术可以利用高效的图像特征匹配算法从多视角照片中提取重叠区域的3维地形数据。由于Sf M技术仅需要目标物体的照片,而且对相机拍摄位置、图像尺度及拍摄焦距没有要求,因此利用简单测量平台采集地面照片就可以获取高质量的3维地形数据。与Li DAR技术相比,大大降低了获取高精度数据的成本,使得高精度3维地形数据的使用大众化。文中介绍了Sf M技术的基本原理和流程,展示了Sf M技术获取高精度3维地形数据的简单而有效的特性,特别适合于植被稀少的区域。文中利用近千米高空拍摄的、具有约70%重叠度的一套随Li DAR飞行采集的数字航空照片生成具有真彩色的高密度Sf M点云数据,点密度高达25.5个/m2,可生成分辨率0.2m的DEM(数字高程模型)。对比相同区域的LiDAR点云数据,统计分析表明58.3%的Li DAR数据与Sf M数据的垂直偏差0.1m,88.3%的Li DAR数据的垂直偏差0.2m;而且发现不同地貌的Sf M数据精度存在差异,平缓地形的Sf M数据精度高于陡峭地形的Sf M数据精度。文中还介绍了以氦气球作为拍摄平台的Sf M测量系统,可以快捷地获取高精度的3D地形数据和正射影像,比目前常用的差分GPS测量具有更高的效率和数据精度。     

岩石气体介质渗透率的瞬态测量方法

测量岩石的渗透率在油田、水利、废物处理和环境工程等领域具有重要意义。在已有的高压孔隙度渗透率测量仪上,根据Darcy定律、状态方程和质量守恒方程,研究了一种气体介质渗透率瞬态测量和计算方法。结果表明,这种方法对低渗透率岩芯测量简单快捷,而且易于推广到温度条件下的渗透率测量。     

断层岩气体渗透率及Klinkenberg效应

在围压2~40MPa变化范围内,以恒流法多次变化上游压力测量了以断层岩为主的样品的气体(N2)渗透率,将实验结果进行了Klinkenberg效应校正。对实验数据的拟合分析表明,滑脱因子b值与绝对渗透率kl存在b=λkl-d形式的幂律关系,断层岩符合b=0.004 6kl-0.476的变化关系。与沉积岩相比,断层岩的气体滑脱效应更强,采用气体测量渗透率时,其滑脱效应不能忽略。断层岩气体渗透率和绝对渗透率与测量所用的孔隙压力间的关系为kg/kl=1+(0.009 2kl-0.476)/(Pu+Pd)。结果表明样品渗透率越低,滑脱效应越强,提高孔隙压力,滑脱效应逐渐减小;对于高渗(10-15m2~10-18m2)的样品,高孔隙压力下(4MPa以上)的气体渗透率与绝对渗透率基本一致,对于超低渗(10-22m2~10-20m2)的样品,即使提高孔隙压力亦很难避免滑脱效应。在40MPa有效压力下断层泥样品的绝对渗透率为4.54×10-19m2~2.43×10-17m2,角砾岩的绝对渗透率较断层泥高出1~2个数量级,为2.25×10-17m2~7.94×10-16m2,表明汶川地震断层带具有核部低、破碎带高的渗透结构,断层带核部具备热压作用发生所要求的低渗条件。     

抽水对体应变的干扰及其消除方法

通过对北京昌平台Ｓａｃｋｓ体应变和气压、水位及抽水资料的综合对比分析，较系统地论述了抽水对体应变年变、月变和日变的干扰作用，并探讨了消除干扰的方法。结果表明，去掉干扰后的体应变曲线与１９８９年大同等地震存在一定的对应性。本文在研究体应变的同时，也研究了地下水位的变化，并比较了二者的异同。