Slope runoff study in situ using rainfall simulator in mountainous area of North China

Simulated rainfall is a valid tool to examine the runoff generation on the slope.13 simulated rainfall experiments with different rainfall intensities and durations are completed in a 5 m ×10 m experimental plot in mountainous area of North China.Simultaneously,rainfall,surface runoff,soil-layer flow,mantel-layer flow and soil moisture are monitored respectively.From the results,it is found that the hydrographs in all layers have the characteristics of rapid rise and fall.The recessions of surface flow and soil-layer flow are much faster than that of mantel-layer flow.Surface flow,the main contributor,makes up more than 60% of the total runoff in the study area.It even exceeds 90% in the cases of high intensity rainfall events.Runoff coefficient(ratio of total runoff to rainfall amount) is mainly influenced by rainfall amount,rainfall intensity and antecedent soil moisture,and the relationship can be well expressed by a multiple linear regression function α = 0.002P + 0.182i + 4.88Wa-0.821.The relation between the rainfall intensity and the lag time of three flows(surface runoff,soil-layer flow and mantel-layer flow) is shown to be exponential.Then,the result also shows that the recession constant is 0.75 for surface runoff,is 0.94 for soil-layer and mantel-layer flow in this area.In this study area,the dominant infiltration excess runoff is simulated by Horton model.About 0.10 mm/min percolation is observed under the condition of different rainfall intensities,therefore the value is regarded as the steady infiltration rate of the study area.     

区域特性约束下的油藏物性模拟

为了提高油藏物性模拟的精度,本文提出了包含两个约束条件的目标函数,考虑在既满足井条件与空间结构变化,同时又满足油田范围内观测到的油藏物理性质的约束下,应用模拟退火算法,对孔隙度的空间分布进行预测模拟.由于目标函数有效地结合了静、动态信息,从而降低了模拟结果的不确定性,提高了模型的精度.合成数据的油藏物性模拟试验表明,该方法收敛快、稳定性好,模拟的结果令人满意.     

改进的约束单纯形-模拟退火剩余静校正

非线性单纯形和模拟退火算法的结合形成了一种新的适合非凸集连续不受约束和受约束函数的全局最优化算法．静校正问题中的相位转移与模拟退火法有明显的相似之处．由非线性单纯形来产生系统的各个状态,在缓慢冷却过程中得到目标函数的全局最优解．所采用的目标函数是道集间的相关,解决了零空间现象．单纯形模拟退火(SIMPSA)算法应用于剩余静校正,收敛速度快,适于解决大剩余静校正．     

基于Ansys Workbench通地1井的绳索取心钻杆接头疲劳分析

通过分析通化盆地地质调查井工程钻探施工工况、钻杆折断事故及折断部位,基于钻杆和钻进工艺参数对井内钻杆接头螺纹受力进行理论计算,采用SolidWorks对钻杆接头螺纹连接处进行建模然后将模型导入Ansys Workbench中进行应力和疲劳仿真分析,预测钻杆接头的疲劳寿命。通过分析仿真结果,再结合地质岩心编录和测井资料,探讨涌水伴随大量气体钻探施工的钻杆折断原因,优化钻进工艺参数,从而减少孔内钻杆折断事故的发生。     

地下工程围岩位移反分析的改进模拟退火算法

本文针对地下工程围岩位移反分析问题的目标函数存在多个局部极值的特点，在对模拟退火算法进程中控制参数，即初始温度、每一温度下的状态选取次数和退火策略的确定方法加以改进的基础上．引进有限元分析手段和自适应的思想，建立了基于改进模拟退火算法的位移反分析方法，并开发了相应的分析程序。工程实践分析表明：本文理论计算结果与实测结果吻合良好，该方法较一般模拟退火算法具有明显的优越性。     

Testing the Validity of Simulated Strong Ground Motion from the Dynamic Rupture of a Finite Fault, by Using Empirical Equations

This paper is concerned with testing the validity of the ground motions estimated by combining a boundary integral equation method to simulate dynamic rupture along finite faults with a finite difference method to compute the subsequent wave propagation. The validation exercise is conducted by comparing the calculated ground motions at about 100 hypothetical stations surrounding the pure strike-slip and pure reverse faults with those estimated by recent ground motion estimation equations derived by regression analysis of observed strong-motion data. The validity of the ground motions with respect to their amplitude, frequency content and duration is examined. It is found that the numerical simulation method adopted leads to ground motions that are mainly compatible with the magnitude and distance dependence modelled by empirical equations but that the choice of a low stress drop leads to ground motions that are smaller than generally observed. In addition, the scatter in the simulated ground motions, for which a laterally homogeneous crust and standard rock site were used, is of the same order as the scatter in observed motions therefore, close to the fault, variations in source propagation likely contribute a significant proportion of the scatter in observed motions in comparison with travel-path and site effects.     

Parameter identification for leaky aquifers using global optimization methods

In the past, graphical or computer methods were usually employed to determine the aquifer parameters of the observed data obtained from field pumping tests. Since we employed the computer methods to determine the aquifer parameters, an analytical aquifer model was required to estimate the predicted drawdown. Following this, the gradient‐type approach was used to solve the nonlinear least‐squares equations to obtain the aquifer parameters. This paper proposes a novel approach based on a drawdown model and a global optimization method of simulated annealing (SA) or a genetic algorithm (GA) to determine the best‐fit aquifer parameters for leaky aquifer systems. The aquifer parameters obtained from SA and the GA almost agree with those obtained from the extended Kalman filter and gradient‐type method. Moreover, all results indicate that the SA and GA are robust and yield consistent results when dealing with the parameter identification problems. Copyright © 2006 John Wiley & Sons, Ltd.     

A THREE-LAYER OCEAN CIRCULATION MODEL APPLICATION TO NUMERICAL STUDIES ON THE NORTH PACIFIC OCEAN CIRCULATION

The formulation and justification of a three-layer baroclinic ocean model developed to simulate thegeneral circulation of the ocean are described in this paper.Test of the model in simulating the annualmean circulation patterns in the North Pacific under the prescribed atmospheric forcing,which consists ofthe climatological surface wind stress and sea surface heat flux,and comparison of the results withobservations showed that the model basically simulated the large scale features of the annual meancirculation patterns in the North Pacific Ocean such as those of the intensified western boundary currentsand the North Equatorial Currents and Undercurrents.But due to the coarse resolution of the model,some details of these currents were poorly reproduced.The seasonal variations of the North Pacific Oceancirculation driven by the seasonal mean sea surface wind stress was calculated,the different aspects of theseresults were analyzed and the main current(the intensified western boundary currents)transports we     

地下水资源系统经济管理模型研究

以乌鲁木齐市柴窝堡供水水源地为例，运用系统分析方法和工程技术经济学原理，从水源地地下水可持续开发利用及水资源与社会经济环境协调发展的角度，探讨水源地合理开发与优化管理问题．研究过程中，在分析研究水源地地下水形成与分布规律的基础上，建立了水源地水地质概念模型与地下水流数学模型：利用长序列观测资料，对地下水流数学模型进行了识别与验证．模型识别与验证中，在进行降速场、梯度场两场同时拟合的情况下，又将水均衡分析结果结合起来，提高了模型的仿真性，保证了利用模型进行预测的可靠性．在此基础上，应用响应矩阵法，将最优化模型与模拟模型相耦合，从水源地开发与社会经济环境协调发展的观点出发，以供水净收益最大为目标函数，建立了水源地地下水资源系统经济管理模型．最后，利用有限元方法，对管理模型运行后产生的方案进行了模拟预测，评价了系统地下水的A级允许开采量．     

Impedance spectroscopy analysis on electrical properties of serpentine at high pressure and high temperature

The electrical conductivity of serpentine is measured and the microscopic conductance mechanisms are investigated with impedance spectroscopy at 2.5–4.0 GPa and 220–780°C. The results show that the electrical conductivity is strongly dependent on the frequencies used, and that only arc I, which reflects grain interior conductance, occurs and dominates the whole conductance processes over 12-10⁵Hz at high pressure before dehydration. The arc II, which indicates the grain boundary process, begins to occur at the initial stage of dehydration. After dehydration, due to the presence of highly conductive networks of free water, the electrical conductivity is not dependent on frequencies any longer and the total electrical conductivity is dominated by process of ionic conductance of free water in interconnected networks. Dehydration of serpentine enhances pronouncedly the total electrical conductivity, through which highly conductive layers (HCL) may be formed in the earth’s interior.