应用单纯形-模拟退火混合算法估计河流水质参数

将由单纯形法(SM)与模拟退火(SA)两种算法构成的混合算法(SMSA),应用于求解分析瞬时投放示踪剂情况下的一维河流水团示踪试验数据,估计河流水质参数的函数优化问题。分别就不同的降温指数、内循环次数与新状态产生函数中的扰动系数等算法控制参数对混合算法和改进模拟退火法的收敛速度的影响,进行了数值实验。结果表明,SMSA混合优化算法对于求解估计河流水质参数的函数优化问题是非常有效的。在实验条件下,与单一具有记忆功能的改进模拟退火法的水质参数计算结果相比较,SMSA混合算法具有:①混合算法的收敛速度明显优于改进模拟退火法;②降温指数和内循环次数对SMSA混合算法的收敛速度影响非常微弱;③新状态产生函数中的随机扰动幅度大小对算法收敛速度具有较为明显的影响等特点。     

Using exploration history to estimate undiscovered resources

Inference about deposits left to be discovered in a partially explored oil field that require only assumptions about the randomness in the exploration procedure are considered. Unbiased estimators, estimators based on partial likelihood methods and confidence procedures are proposed.     

Using operational data to estimate the reliable yields of water-supply wells

The reliable yield of a water-supply well depends on many different factors, including the properties of the well and the aquifer; the capacities of the pumps, raw-water mains, and treatment works; the interference effects from other wells; and the constraints imposed by abstraction licences, water quality, and environmental issues. A relatively simple methodology for estimating reliable yields has been developed that takes into account all of these factors. The methodology is based mainly on an analysis of water-level and source-output data, where such data are available. Good operational data are especially important when dealing with wells in shallow, unconfined, fissure-flow aquifers, where actual well performance may vary considerably from that predicted using a more analytical approach. Key issues in the yield-assessment process are the identification of a deepest advisable pumping water level, and the collection of the appropriate well, aquifer, and operational data. Although developed for water-supply operators in the United Kingdom, this approach to estimating the reliable yields of water-supply wells using operational data should be applicable to a wide range of hydrogeological conditions elsewhere. Received, September 1998/Revised, May 1999, September 1999/Accepted, October 1999     

Using fault displacement and slip tendency to estimate stress states

We suggest that faults in high slip tendency orientations tend to develop larger displacements than other faults. Consequently, faults that accumulate larger displacements are more likely to be reliable indicators of the longer term stress field and should be weighted accordingly in paleostress estimation. Application of a stress inversion technique that uses slip tendency analyses and fault displacements to interpret populations of coherent normal faults within the Balcones Fault System of south-central Texas provides stress estimates that are consistent with established regional stress analyses. Although the method does not require measurement of slip directions, these data, where available, and sensitivity analyses of the angular mismatch between measured slip directions and those predicted by inverted stress states provide high confidence in the stress estimates generated using slip tendency analyses. Close inspection of the fault orientation and displacement data further indicates that subpopulations of faults with orientations different from the regional pattern have formed in response to stress perturbations generated by displacement gradients on an adjacent seismic scale fault.     

Using strain birefringence in diamond to estimate the remnant pressure on an inclusion

Abstract

The Upper Triassic Chang 8 Member, the eighth member of the Yanchang Formation, is a key reservoir interval in the Jiyuan area of the Ordos Basin. The reservoir quality of the Chang 8 Member tight sandstones is extremely heterogeneous owing to the widespread distribution of carbonate cements. The carbonate cements commonly develop near sandstone–mudstone interfaces and gradually decrease away from the interfaces to the centres of the sand bodies. However, the content of carbonate cements (≤6%) has a positive correlation with the visual porosity in the Chang 8 Member sandstone, revealing that the carbonate cements contribute to the compaction resistance and the residual primary pores of reservoirs during the diagenetic process. Three main types of carbonate cement are identified: type I (calcite), type II (calcite and ferrocalcite), and type III (dolomite and ankerite). The type I calcite is characterised by enriched δ¹³C (mean –3.41‰) and δ¹⁸O (mean –15.17‰) values compared with the type II (mean δ¹³C?=?–7.33‰, δ¹⁸O?=?–18.90‰) and type III (mean δ¹³C?=?–10.0‰, δ¹⁸O?=?–20.2‰) cements. Furthermore, the mean δ¹⁸O value (–4.7‰) of the type I pore fluids is 1.5‰ and 0.9‰ lower than the type II (mean –3.2‰) and type III (mean –3.8‰) pore fluids, respectively. This indicates that the evolving pore fluids experienced some relative strong water–rock interactions that provided the original materials (e.g. Ca²⁺, Fe³⁺, and Mg²⁺) for the carbonate cements during the diagenetic process. The highly saline lake water directly provided the primary material for the type I calcite precipitation, which also provided the material necessary for the precipitation of the type II and type III carbonate cements, causing enriched δ¹⁸O values of the pore fluids during the precipitation of the type II and type III carbonate cements. Although the earlier dissolved pores were filled with ferrocalcite, dolomite and ankerite in the middle–late diagenetic stages, some residual pores and fractures remained to become the potential reservoir storage spaces for the oil and gas exploration in the Jiyuan area.     

A four elements porous model to estimate the strength of unsaturated soils

One of the most prevalent relationships for effective stresses on unsaturated soils was proposed by Bishop in the middle of the last century. However, only recently Bishop’s effective stress equation has been implemented in various constitutive models for unsaturated soils. These models have the advantage of naturally including the hydro-mechanical coupling that has been experimentally observed on these materials. Unfortunately, the problem of properly evaluating Bishop’s parameter χ still remains unsolved. This paper presents the results of a solid-porous model used to determine the value of Bishop’s parameter χ and evaluate the strength of unsaturated soils. These theoretical results are compared with a series of triaxial test performed on a silty sand subjected to different suctions in wet and dry paths. These comparisons show that the porous model proposed herein can be used to estimate the strength of unsaturated soils for both the wetting and the drying paths.     

运用统计分析法与Lumpfit模型计算烟台于家汤热泉可采资源量

于家汤地热田因地热流体的大量开采已出现水位、水温下降的现象,如何准确评价其可采资源量是地热田可持续开发的首要任务。本文基于于家汤地热田2006～2016年的水位、水温、水质、水量等长期动态观测资料,采用统计分析法计算得出该地热田在温度不低于38℃时的最大允许水位埋深为19 m;利用Lumpfit集中参数模型模拟得出地热田在保持现有平均开采量不变的条件下,水位最大埋深可达14. 5 m;反演计算水位埋深降至19 m时的可采资源量为1523 m3/d,同时通过地热田多观测孔抽水试验解析法计算地热田可采资源量与之对比,充分证明本次研究采用方法的可靠性,从而为于家汤地热田的合理开发利用地热资源提供参考依据。     

A time-series analysis framework for the flood-wave method to estimate groundwater model parameters

The flood-wave method is implemented within the framework of time-series analysis to estimate aquifer parameters for use in a groundwater model. The resulting extended flood-wave method is applicable to situations where groundwater fluctuations are affected significantly by time-varying precipitation and evaporation. Response functions for time-series analysis are generated with an analytic groundwater model describing stream–aquifer interaction. Analytical response functions play the same role as the well function in a pumping test, which is to translate observed head variations into groundwater model parameters by means of a parsimonious model equation. An important difference as compared to the traditional flood-wave method and pumping tests is that aquifer parameters are inferred from the combined effects of precipitation, evaporation, and stream stage fluctuations. Naturally occurring fluctuations are separated in contributions from different stresses. The proposed method is illustrated with data collected near a lowland river in the Netherlands. Special emphasis is put on the interpretation of the streambed resistance. The resistance of the streambed is the result of stream-line contraction instead of a semi-pervious streambed, which is concluded through comparison with the head loss calculated with an analytical two-dimensional cross-section model.     

Application of WetSpass model to estimate groundwater recharge variability in the Nile Delta aquifer

Long-term groundwater recharge from rainfall in the Nile Delta is needed as an input for integrated groundwater modelling in the Nile Delta aquifer for more accurate simulation. The main objective is to estimate the spatial and temporal variation of groundwater recharge from rainfall in the Nile Delta aquifer. Water and Energy Transfer between Soil, Plants and Atmosphere under quasi-Steady State (WetSpass) model parameters were identified for the Nile Delta based on the available meteorological data for the area collected in 1991 and 2000. The collected data were rainfall, temperature, wind speed and evapotranspiration. Geomorphological characteristics, such as soil type, topography, groundwater depth and slope, were also collected as input data for the WetSpass model. ENVI software was used to come up with land use classification based on available land cover images of the Nile Delta for 1972, 1984, 1990, 2000 and 2009. The WetSpass model was calibrated by comparing the simulated groundwater recharge with the calculated one by using the water balance equation model. The results indicated close agreement in groundwater recharge between the two model outputs with R ² of 0.99 and 0.94, while the root-mean-square errors (RMSEs) were 4.86 and 9.39 mm for 1991 and 2000, respectively. The WetSpass model was then applied in respect of 1970, 1980, 1990 and 2010 for the purpose of validation. The overall RMSE and R ² for the 6 years were 8.83 mm and 0.88, respectively. The results of the WetSpass calibrated model provide information to support integrated groundwater modelling. The results reveal that WetSpass works well in simulating the components of the hydrological balance in the Nile Delta.     

基于扩展Lagrange乘子的Clough接触面模型及应用

双曲线接触面本构模型能比较真实地模拟堆石材料与混凝土面板间的接触关系,扩展Lagrange乘子法能比较精确地计算接触面间接触状态。在吸取Clough双曲线接触面本构关系应用于无厚度的Goodman单元和有厚度的Desai薄层单元的成功经验的基础上,将Clough双曲线接触面模型引入扩展Lagrange乘子法进行摩擦接触问题的求解。介绍了基于扩展Lagrange乘子法的序列二次规划法（SQP）提法,详细推导了在扩展Lagrange算法的非线性接触计算中引入Clough双曲线接触面本构关系的数值列式和实施步骤。数值算例和工程实例的计算结果证明该方法是成功的,能够比较真实地模拟堆石-混凝土墙（混凝土面板）之间的接触状态。     

利用全概率方法分析岩土力学数值模拟结果的变异性

提出了一种用于分析在多参数随机情况下岩土力学数值模拟结果变异性的全概率方法。以特定数值模拟结果为随机隐式响应量,根据多维高效数值求积理论,计算出响应量特定函数的均值,利用快速傅里叶变换数值概率分析方法及笔者开发的最大熵分布,求解器软件一次性求解出响应量的全概率分布,用于定量评估数值模拟结果的变异性。算例表明该法具有精度和计算效率较高的优点。     

Four cultures: the evolution of a parsimonious model

Cultural theory works with a parsimonious model of four cultural types, each emanating from a specific form of organisation. The four types are identified as attitudes and values that justify the organisation. The hierarchical type, with its ranked levels and symmetrical branchings, depends on the adoption of hierarchical values and the expression of matching judgements. Likewise for the enclavist culture, the individualist culture and that of the isolates. There is no assumption of fixity, on the contrary, the four types are represented in any community, and social life is in permanent tension and flux. This article gives a summary of the early history of the theory. This revised version was published online in August 2006 with corrections to the Cover Date.     

利用声波测井计算岩石的力学参数

介绍了岩石力学参数的测量方法及岩石动、静弹性参数相关关系,最后用实际声波测井资料来分析计划岩石的力学参数。     

The use of the specific interaction model to estimate the partial molal volumes of electrolytes in seawater

The specific interaction model has been used to determine the partial molal volume of electrolytes in 0.725 m NaCl and 35‰ salinity seawater solutions at 25°C. The partial molal volumes of electrolytes (MX) were estimated at a given ionic strength (I) from

$\text{V}\text{(}\text{MX}\text{) =}\text{V}{}^0\text{(}\text{MX}\text{) +}\text{S}{}_{\mathrm{v}}\text{I}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(1 + I}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}\text{+ v}{}_{\mathrm{M}}\text{∑}\text{X}\text{B}{}_{\mathrm{<mtext>MX</mtext>}}\text{[X] + v}{}_{\mathrm{X}}\text{∑}\text{M}\text{B}{}_{\mathrm{<mtext>MX</mtext>}}\text{[X]}$

, where S_V is the Debye-Hückel limiting law slope, v_i is the number of ions i formed when MX dissociated, [i] is the total molality of ion i and B_MX is a specific interaction parameter that varies slowly with ionic strength. The values of $\text{V}\text{(}\text{MX}\text{)}$ estimated by using this equation were found to agree very well with experimental values in NaCl and seawater providing there are not strong interactions between M and X. For electrolytes that form ion pairs (i.e. MX°) corrections must be made. Methods are discussed for making these corrections.     

Using pore-solid fractal dimension to estimate residual LNAPLs saturation in sandy aquifers: A column experiment

The“tailing”effect caused by residual non-aqueous phase liquids(NAPLs)in porous aquifers is one of the frontiers in pollution hydrogeology research.Based on the current knowledge that the residual NAPLs is mainly controlled by the pore structure of soil,this study established a method for evaluating the residual saturation of NAPLs by investigating the fractal dimension of porous media.In this study,the soil column experiments of residual light NAPLs(LNAPLs)in sandy aquifer with different ratios of sands and soil were carried out,and the correlation between the fractal dimension of the medium,the residual of LNAPLs and the soil structure parameters are statistically analyzed,and its formation mechanism and main control factors are discussed.The results show that:Under our experimental condition:(1)the fractal dimension of the medium has a positive correlation with the residual saturation of NAPLs generally,and the optimal fitting function can be described by a quadratic model:S_R=192.02 D2-890.73 D+1040.8;(2)the dominant formation mechanism is:Smaller pores in the medium is related to larger fractal dimension,which leads to higher residual saturation of NAPLs;stronger heterogeneity of the medium is related to larger fractal dimension,which also leads to higher residual saturation of NAPLs;(3)the micro capillary pores characterized by fine sand are the main controlling factors of the formation mechanism.It is concluded that both the theory and the method of using fractal dimension of the medium to evaluate the residual saturation of NAPLs are feasible.This study provides a new perspective for the research of“tailing”effect of NAPLs in porous media aquifer.     

引入接触单元模拟桩土共同作用

在桩与桩侧土界面引入接触单元模型，并采用参变量变分原理及基于此原理的参变量二次规划法，对接触单元刚度矩阵进行了推导。模型计算结果与实测比较表明，接触单元能较好地模拟桩与土之间的剪力传递和相对位移。     

用遗传算法优化估计Van Genuchten方程参数

描述土壤水分特征曲线的Van Genuchten方程是一个非线性复杂方程,采用传统的方法对方程参数进行估计往往因为计算复杂和人为因素的影响,而使估计结果带有较大的误差。遗传算法是当前处理一般非线性数学模型优化的一种新的优秀方法。为此,采用实数编码多子种群遗传算法对方程的参数进行优化估计。算例结果表明用遗传算法优化估计Van Genuchten方程参数具有求解速度快、计算精度和自动化程度高、人为干扰因素小、通用性强等优点。因此,遗传算法可作为计算Van Genuchten方程参数的一种新方法。     

Analysis of rectangular piles subjected to lateral loads in nonhomogeneous soil using a Winkler model approach

An analytical approach using a Winkler model based on two lateral soil displacement components in a three‐dimensional soil is investigated to provide analytical solutions of horizontal response of a rectangular pile subjected to lateral loads in nonhomogeneous soil. The two lateral displacement components of a soil surrounding the rectangular pile are represented by the Fourier series of displacement potential functions in the elastic three‐dimensional analysis. The lateral stiffness coefficient of the rectangular pile shaft in nonhomogeneous soil is derived from the rocking stiffness coefficient taking into account rocking rotation of a rigid pile shaft. The relationship between horizontal displacement, rotation, moment, and shear force for the rectangular pile subjected to horizontal loads in nonhomogeneous soil is obtainable in the form of the recurrence equation. The formulation of lateral displacement and rotation for a rectangular pile subjected to lateral loads on the pile base in nonhomogeneous soil is proposed by taking into account Mindlin's equation and the equivalent thickness for soil layers in the equivalent elastic method. The difference of lateral behavior between square and circular piles subjected to lateral loads is insignificant. The effect of aspect ratio of the rectangular pile on the lateral behavior is great for the lower stiffness ratio between pile and soil and the larger length–equivalent diameter ratio. The effect of the value of Poisson's ratio of soil on lateral stiffness coefficient is relatively small except Poisson's ratio close to 0.5. The comparison of the results calculated by the current method for a rectangular pile subjected to lateral loads in nonhomogeneous soil has shown good agreement with those obtained from the analytical methods and the finite element method. Copyright © 2015 John Wiley & Sons, Ltd.     

Using remote sensing to quantify aeolian transport and estimate the age of the terminal dune field Dunas Pampa Blanca in southern Peru

Aeolian dunes are widely used to reconstruct paleoenvironmental conditions. However, terminal dune fields (ergs) in the coastal desert of southern Peru – where information regarding Quaternary paleoenvironmental conditions is very limited – have until now not been used for paleoenvironmental reconstructions and the time depth of their accumulation is unknown. Here, different estimates are derived to constrain the time depth recorded in the Dunas Pampa Blanca, a terminal dune field in coastal southern Peru. Dune field age is calculated using the volume of the Dunas Pampa Blanca and (i) recent aeolian transport rate in migrating transverse dunes feeding the Dunas Pampa Blanca (derived from digital processing of sequential Landsat and Quickbird images) and (ii) limitations posed by recent fluvial sediment supply to the source of aeolian transport. The resulting maximum age estimate of 70 ± 8 ka (from aeolian transport) compares with a minimum age estimate of 4–75 ka (from sediment supply). However, a minimum age estimate of 110–450 ka is deduced from the tectonic and topographic evolution of the region. This discrepancy contradicts the hypothesis of late Quaternary stability in the Peruvian coastal desert and indicates that recent conditions of aeolian sediment supply and transport are not representative for the late Quaternary.