Laboratory model tests for cyclic load-induced settlement of a strip foundation on a clayey soil

Laboratory model test results are presented for the cyclic load-induced settlement of a strip foundation supported by a saturated clayey soil. In performing the tests, the foundation was initially subjected to an allowable static load, after which a cyclic load with a frequency of one cycle per second was superimposed on it. The magnitudes of the static load and the amplitude of the cyclic load were varied. Based on the model test results, relationships for the foundation settlement and intensities of the static and cyclic loads are presented.     

成像光谱遥感数据的光谱重建研究

成像光谱遥感数据处理中的一个重要环节是大气辐射纠正，它是成像光谱遥感定量化的重要部分，本文推导出一种简单的方法，对高光谱分辨率航空遥感图象进行大气纠正，反射率图像转换及光谱重建，并在地质资源遥感调查中应用，取得很好的效果，同时，对重建的地物光谱中出现的误差，进行了分析。     

Bed load transport in braided gravel-bed stream models

Bed load transport rate was measured in ten self-formed small-scale gravel braided streams developed in a laboratory flume at several different values of steady discharge and flume gradient. The streams are approximate Froude models of typical prototype braided streams but of no particular river. Slight viscous effects may be present in the models because particle Reynolds numbers are close to 70. Total bed load discharge was measured every fifteen minutes throughout each 60 hour run. In addition, 80 channel cross-sections were measured in each run to establish the average channel geometry. Total bed load transport rate correlates well with total discharge and total stream power, although at a given stream power bed load discharge is greater when braiding is less intense and the width/depth ratio is lower. Analysis using unit stream power and cross-section average bed shear stress reveals that the laboratory data conform to existing empirical bed load transport relationships. However, comparison with field data from gravel-bed rivers shows discrepancies that may be due to differences in bed material size gradation and bed sediment structure. At constant discharge, wide fluctuations in bed load discharge occur with some regularity. Periods range from 2 to 10 hours in the models, which is equivalent to several tens of hours in a prototype. The presence of these long-period fluctuations compounds the problems of field measurement of bed load in braided streams.     

从栅格数据直接建立拓扑关系的算法研究

本文提出了从栅格数据直接建立拓扑关系的思想,用跟踪过程中容易获得的拓扑信息来优化拓扑生成的算法模型,借以提高拓扑生成的效率。本文还提出用连通性区域填充的方法处理各种任意复杂岛的思想。     

四川乐山建材非金属矿产资源的勘查与开发利用前景

概述了乐山建材非金属矿产资源的主要特征，阐明了其勘查与开发利用现状，并对资源形势作了分析，进而论述勘查与开发利用的前景。     

软粘土中钻孔灌注桩承载特性的试验研究

基于埋设有测试元件的足尺钻孔灌注桩的现场静载荷试验 ,研究了软粘土地层中桩长 2 8m ,桩径 6 0 0mm钻孔灌注桩的承载力 -沉降性质 ,同时研究了试桩的荷载传递特性 ,分析了桩身轴力、桩侧阻力及桩端阻力的发挥规律 ,并就单桩的沉降变形进行了计算分析 ,得到了一些有益的结论。     

移动荷载作用下半无限体的动力响应解

以Duhamel积分为基础，采用Fourier变换和Floquet变换等方法，给出了移动荷载作用下半无限体中任一点的动力响应在时域、频域和频率-波数域内的表达式。该公式的推出，在交通荷载作用下，可为土体和结构的动力响应分析提供一定的理论基础。     

Steady-state response of a stratified half-space subjected to a horizontal arbitrary buried uniform load applied at a circular area

This paper outlines a method of analysis of the steady-state dynamic response of a stratified soil to a horizontal time-harmonic loading applied at a circular area. It is assumed the load to be uniformly distributed over the contact area and embedded at an arbitrary depth. It is shown that by means of application of integral Hankel transform, the problem can be reduced to a form of a single integral, which can be taken numerically. Results of the numerical simulations for an embedded horizontal impulse load are presented to demonstrate the efficiency of the developed procedure.     

Capacity evaluation of statnamic tested long piles

A procedure that uses the structural damping (SD) concept for estimating the capacity of a pile based on the Statnamic (STN) pile load test results, formerly used by the authors for short piles, is extended in this paper for the STN tested long piles. Similar to segmental unloading point method procedures for long piles, the shaft length is divided into several segments and each segment is assumed to behave as a mass of a single degree of freedom. The SD concept is then applied to each segment to consider the displacement related soil damping instead of the velocity dependent damping. Instrumented strain gauge data at different levels of the shaft are required for the interpretation method. Three case studies are presented in this paper to study the validity and applicability of the present method. The predicted results are also compared to the available test or analytical data.     

ROOF BOUNDARY EXTRACTION USING MULTIPLE IMAGES

Urban area building extraction is one of the most challenging problems in photogrammetry. Well-extracted buildings are needed for a variety of applications, such as cartography, building GIS databases for cities, and urban planning. This paper presents a new technique to extract 3D building wire-frames using a robust multi-image line-matching algorithm. Although one pair of images is adequate to find the 3D position of two visibly corresponding image features, it is not sufficient to solve the general building extraction problem due to obscured parts in the building. Four images are used in this research to extract the building wire-frames. First the images are segmented into regions. Regions are then classified into roof regions and non-roof regions based on their size, shape, and intensity values. The roof region boundary pixels are located and used to find the region perimeters. Region correspondence is solved in a pair-wise mode over all images using the epipolar constraint, region size, region shape, and region intensity values. Image lines within the corresponding regions are matched over all images simultaneously by first creating a plane for each region line. Planes are then intersected simultaneously and geometric consistency is used to determine acceptance or rejection. Results with high overlap and sidelap aerial images are presented and evaluated. The results show the completeness and accuracy that this method can provide for extracting complex urban buildings. The average coordinate accuracy is about 0·8 m using 1:4000 scale aerial photographs scanned at 30 μ m. Six buildings were examined; the line detection rate is 98%.