Rocking response of flexible circular foundations on layered media

The analysis of the response of a flexible circular foundation on layered media due to an arbitrarily distributed vertical loading is presented. The analysis is based on the ‘ring method’ approach, i.e. discretization of the foundation in a set of concentric rings. The arbitrarily distributed loading is expanded in the circumferential direction in a Fourier series. The influence coefficient matrix of soil for each element of the series is evaluated utilizing the stiffness matrix approach. The stiffness matrix of the foundation is obtained from the finite difference energy method approach. Numerical examples illustrate the influence of several soil-foundation parameters on the rocking response of a foundation. Results are presented in terms of displacement and soil reaction distributions and impedance functions point to significantly different responses of flexible and rigid foundations.     

我国日照时数和总辐射的空间分布场

运用多项式回归分析和双随机样本检验,模拟日照时数和总辐射及其影响因子(可照时间、总云量和天文辐射、日照百分率)年值和1月值、7月值的三度空间分布场,取得了满意结果。这可应用在无测站地区,仅凭经纬度和海拔估算出上述气候要素值,估算的平均相对误差大多在5％以下(最好的达0.3‰)。     

Appraisal of Seismic Hazard Parameters for the Seismic Regions of the East Circum-Pacific Belt Inferred from a Bayesian Approach

The assessment of seismic hazard parameters is important in the seismically active regions. A straightforward approach is considered for the statistical estimation of the maximum values of earthquake hazard parameters. The Bayesian estimator is suggested and emphasis is given to the evaluation of the maximum possible M_max (regional) magnitude in a future time interval T. This approach allows the uncertainty of earthquake magnitude to be accounted for. Seismic hazard parameters like the -value which is the slope of the magnitude-frequency law (where, b = log_e) and the intensity (rate) of seismic activity and their uncertainties are also estimated. The quantiles of functions of distributions of true and apparent magnitude on a given time interval [0, T] are evaluated, as well. Two main assumptions are adopted for the method:(1) earthquake occurrence is Poissonian and(2) the magnitude-frequency law is of Gutenberg-Richter type with a cutoff maximum value of magnitude. It is needless to say the seismic catalog used must have a large number of events. This requirement leads to the estimation of the parameters referred to some of the most seismically active regions of the world, e.g., Chile, Peru-Equador-South Colombia,Central America and Mexico, which belong to the east part of the circum-Pacific belt.     

Regionalization of rainfall thresholds: an aid to landslide hazard evaluation

 Rainfall, soil properties, and morphology are major factors controlling shallow landsliding. A series of meteorological events that triggered soil slips in northern Italy were studied to define rainfall thresholds and to evaluate a possible regionalization. Soil properties, triggering rainfall, and local lithological and morphometrical settings of different sites were used as input to an infiltration model. The approach allows the recognition of several triggering conditions in the Piedmont, Pre-Alpine and Alpine regions. This suggests the need for different rainfall thresholds with respect to those derived with other methods. Intensity versus rainfall duration relationships become particularly important when related to soil permeability and thickness, and demonstrate the role of antecedent precipitation. Events with exceptional water discharge from obstructed road culverts reveal the role played by anthropic structures in triggering such phenomena. Different approaches to slope stability analysis are shown, taking into account bedrock lithology, topography, seepage, and local saturation conditions. Received: 23 October 1997 · Accepted: 25 June 1997     

数字抽取滤波器的DSP优化设计

为了降低地震数据采集系统的成本和功耗，采用数字信号处理器（DSP）实现∑-△模数转换器中的数字抽取滤波器算法。通过采取查表法、倒序循环遍历法以及模拟循环寻址法等优化方法，以较低工作频率实现了四通道四级抽取滤波运算，达到了系统设计的要求。     

弧形防波堤波浪力试验研究

在圆筒形防波堤和V形防波堤的基础上,结合离岸堤后形成V形和半圆形连续出现的韵律海岸的地貌平面形态特点,提出一种前墙为连续的半圆筒形防波堤形式。通过在波浪水槽内进行规则波物理模型试验,探究这一新型防波堤的波压力分布规律及波高、周期、水深等因素对波压力的影响。将试验结果与海港水文公式和合田良实公式计算的理论值对比分析,给出了以合田良实公式的折减系数来拟合新型弧形防波堤波浪总水平力的计算公式。结果表明:新型弧形防波堤上的波压力随波高、周期的增大而增大,其水平波浪总力比同等尺度直墙少10%左右。     

文登市全面推行“三全”执法责任制

为加强做好国土资源执法监察工作,文登市国土资源局在认真贯彻落实好国土资源部执法监察各项规定的同时,在建立健全村级土地协管员、信访信息员、土地监督员的基础上,全市全面推行＂分级负责,层层监管＂的执法新机制,动员全社会力量参与国土资源管理,变国土部门一家管为大家管,扭转了国土资源执法监察工作的被动局面,是当前做好国土资源执法监察工作的有效途径。     

深度学习支持下的宅基地复垦项目真实性智能审查技术研究与应用

全域综合整治背景下的宅基地复垦项目审查是保证复垦项目合法性合规性的有效手段,针对当前宅基地复垦项目审查效率低的问题,本文提出了基于遥感影像的农村宅基地复垦项目立项真实性审查方法。首先以重庆市农村宅基地复垦项目为例,建立宅基地复垦项目立项真实性审查模型,利用改进的U-Net模型准确提取建筑物,然后与复垦红线叠加实现复垦项目真实性的智能审查。试验结果表明,该方法能够快速准确地审查复垦项目真实性,对优化土地结构、促进土地流转、实现乡村振兴具有重要意义,可为全域综合整治背景下宅基地复垦项目真实性审查提供技术参考。     

河南熊耳山北部上观环形构造及其找矿意义

河南省西部的熊耳山地区是重要的金成矿集中区,区内环形-线性构造与成矿存在耦合关系。本研究中对最新高分SPOT-5图像和Aster的遥感地质解译发现,熊耳山北部上观周围区域存在多个环形构造,主要发育于太华群古老变质岩和熊耳群火山岩中,南部附近为中生代花山岩体。环形构造集中分布,大环套小环、线性和环形构造交切。影像蚀变信息提取研究发现,环形构造周围及其内部发育较好的铁染异常和羟基异常,具有良好的找矿前景。附近和周围已知的金矿床和金矿点零星分布,但其遥感图像与熊耳山其他类似环形构造发育地区相比,影像特征更为典型,且成矿条件似更为优越,有可能成为熊耳山地区又一个金银成矿集中区。     

Study on deformation law of circular foundation under combined loading

The foundations of some ocean engineering structures are built to withstand not only the vertical gravity load V, but also the horizontal load H induced by sea waves and current. The horizontal load includes the concentrated force load, the moment load M, and the torque load T termed also as combined loading. It is of academic and engineering significance to study the deformation law of submarine seabed due to combined loading. On the basis of the three-dimensional elastic mechanics solution of circular foundation, numerical methods are used to analyze the deformation law of submarine soil under circular foundation with six degrees of freedom. The finite element analysis results give the elastic deformation law of soil in three dimensional spaces, modify the theoretical elasticity solution, and presents nonlinear soil deformation mechanism under the circular foundation with six degrees of freedom.