Fuzzy and Multiple Regression Modelling for Evaluation of Intact Rock Strength Based on Point Load, Schmidt Hammer and Sonic Velocity   总被引：4，自引：0，他引：4  

M. Karakus  B. Tutmez 《Rock Mechanics and Rock Engineering》2006,39(1):45-57

Summary. Uniaxial Compressive Strength (UCS), considered to be one of the most useful rock properties for mining and civil engineering applications, has been estimated from some index test results by fuzzy and multiple regression modelling. Laboratory investigations including Uniaxial Compressive Strength (UCS), Point Load Index test (PL), Schmidt Hammer Hardness test (SHR) and Sonic velocity (V_p) test have been carried out on nine different rock types yielding to 305 tested specimens in total. Average values along with the standard deviations (Stdev) as well as Coefficients of variation (CoV) have been calculated for each rock type. Having constructed the Mamdani Fuzzy algorithm, UCS of intact rock samples was then predicted using a data driven fuzzy model. The predicted values derived from fuzzy model were compared with multi-linear statistical model. Comparison proved that the best model predictions have been achieved by fuzzy modelling in contrast to multi-linear statistical modelling. As a result, the developed fuzzy model based on point load, Schmidt hammer and sonic velocity can be used as a tool to predict UCS of intact rocks.  相似文献   

Nitrate pollution and its distribution in the groundwater of Srikakulam district, Andhra Pradesh, India   总被引：3，自引：0，他引：3  

Nagireddi Srinivasa Rao 《Environmental Geology》2006,51(4):631-645

The complex depositional pattern of clay and sand in most of the areas controlled the vertical and lateral movement of nitrate in groundwater. The variation of nitrate concentration at different groundwater levels and the lateral distribution of nitrate in the groundwater at two sites indicated the filtration of nitrate by clayey formations. A rural agricultural district located in the Vamsadhara river basin, India was selected for studying the lateral and vertical distribution of nitrate in the groundwater and the association of nitrate with other chemical constituents. The nitrate concentrations in the groundwater are observed to vary between below detectable limit and 450 mg NO₃/L. The sources for nitrate are mainly point sources (poultry farms, cattleshed and leakages from septic tanks) and non-point sources (nitrogenous fertilisers). The nitrate concentrations are increased after fertiliser applications. However, very high concentrations of nitrate are derived from animal wastes. Relatively better correlations between nitrate and potassium are observed (R = 0.74 to 0.82). The better relationship between these two chemical constituents in the groundwater may be due to the release of potassium and nitrate from both point and non-point sources. The nitrate and potassium concentrations are high in the groundwater from clayey formations.  相似文献   

Bayesian analysis of marked stress release models for time-dependent hazard assessment in the western Gulf of Corinth     

R. Rotondi  E. Varini   《Tectonophysics》2006,423(1-4):107

We consider point processes defined on the space–time domain which model physical processes characterized qualitatively by the gradual increase over time in some energy until a threshold is reached, after which, an event causing the loss of energy occurs. The risk function will, therefore, increase piecewise with sudden drops in correspondence to each event. This kind of behaviour is described by Reid's theory of elastic rebound in the earthquake generating process where the quantity that is accumulated is the strain energy or stress due to the relative movement of tectonic plates. The complexity and the intrinsic randomness of the phenomenon call for probabilistic models; in particular the stochastic translation of Reid's theory is given by stress release models. In this article we use such models to assess the time-dependent seismic hazard of the seismogenic zone of the Corinthos Gulf. For each event we consider the occurrence time and the magnitude, which is modelled by a probability distribution depending on the stress level present in the region at any instant. Hence we are dealing here with a marked point process. We perform the Bayesian analysis of this model by applying the stochastic simulation methods based on the generation of Markov chains, the so called Markov chain Monte Carlo (MCMC) methods, which allow one to reconcile the model's complexity with the computational burden of the inferential procedure. Stress release and Poisson models are compared on the basis of the Bayes factor.  相似文献   

3维激光扫描技术在工程应用中的精度探讨     

程光亮  张福利  王宝山 《测绘与空间地理信息》2007,30(4):25-27,32

介绍了3维激光扫描仪的原理及获取转换3维坐标的原理,通过3维激光扫描技术在工程中的应用实验;对3维激光扫描技术提出了一点总结性看法。  相似文献   

桩身轴向应变的连续监测法     

李光煜  陈东 《地震工程学报》2011,33(Z1)

静力试桩中桩身轴向应变是分析荷载传递机理的基础。滑动测微计可连续地测定桩身每米内的平均应变,通过荷载-应变关系曲线可较准确地计算轴向力、摩阻力、端阻力、负摩阻力;水平试桩时安装二条测管可准确地推算挠度曲线、最大弯矩点,临界荷载、极限荷载等桩基设计的主要参数,还可全面地评价桩身质量。该仪器不仅可用于各类试桩,还可用于各类岩土工程的现场位移监测。  相似文献   

A global optimization approach to roof segmentation from airborne lidar point clouds     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

This paper presents a global plane fitting approach for roof segmentation from lidar point clouds. Starting with a conventional plane fitting approach (e.g., plane fitting based on region growing), an initial segmentation is first derived from roof lidar points. Such initial segmentation is then optimized by minimizing a global energy function consisting of the distances of lidar points to initial planes (labels), spatial smoothness between data points, and the number of planes. As a global solution, the proposed approach can determine multiple roof planes simultaneously. Two lidar data sets of Indianapolis (USA) and Vaihingen (Germany) are used in the study. Experimental results show that the completeness and correctness are increased from 80.1% to 92.3%, and 93.0% to 100%, respectively; and the detection cross-lap rate and reference cross-lap rate are reduced from 11.9% to 2.2%, and 24.6% to 5.8%, respectively. As a result, the incorrect segmentation that often occurs at plane transitions is satisfactorily resolved; and the topological consistency among segmented planes is correctly retained even for complex roof structures.  相似文献   

An adaptive surface filter for airborne laser scanning point clouds by means of regularization and bending energy     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

The filtering of point clouds is a ubiquitous task in the processing of airborne laser scanning (ALS) data; however, such filtering processes are difficult because of the complex configuration of the terrain features. The classical filtering algorithms rely on the cautious tuning of parameters to handle various landforms. To address the challenge posed by the bundling of different terrain features into a single dataset and to surmount the sensitivity of the parameters, in this study, we propose an adaptive surface filter (ASF) for the classification of ALS point clouds. Based on the principle that the threshold should vary in accordance to the terrain smoothness, the ASF embeds bending energy, which quantitatively depicts the local terrain structure to self-adapt the filter threshold automatically. The ASF employs a step factor to control the data pyramid scheme in which the processing window sizes are reduced progressively, and the ASF gradually interpolates thin plate spline surfaces toward the ground with regularization to handle noise. Using the progressive densification strategy, regularization and self-adaption, both performance improvement and resilience to parameter tuning are achieved. When tested against the benchmark datasets provided by ISPRS, the ASF performs the best in comparison with all other filtering methods, yielding an average total error of 2.85% when optimized and 3.67% when using the same parameter set.  相似文献   

Image-based correlation of Laser Scanning point cloud time series for landslide monitoring     

《International Journal of Applied Earth Observation and Geoinformation》2014

Very high resolution monitoring of landslide kinematics is an important aspect for a physical understanding of the failure mechanisms and for quantifying the associated hazard. In the last decade, the potential of Terrestrial Laser Scanning (TLS) to monitor slow-moving landslides has been largely demonstrated but accurate processing methods are still needed to extract useful information available in point cloud time series. This work presents an approach to measure the 3D deformation and displacement patterns from repeated TLS surveys. The method is based on the simplification of a 3D matching problem in a 2D matching problem by using a 2D statistical normalized cross-correlation function. The computed displacement amplitudes are compared to displacements (1) calculated with the classical approach of Iterative Closest Point and (2) measured from repeated dGPS observations. The performance of the method is tested on a 3 years dataset acquired at the Super-Sauze landslide (South French Alps). The observed landslide displacements are heterogeneous in time and space. Within the landslide, sub-areas presenting different deformation patterns (extension, compression) are detected by a strain analysis. It is demonstrated that pore water pressure changes within the landslide is the main controlling factor of the kinematics.  相似文献   

RTKLIB 软件静态精密单点定位精度测试与分析     

张建龙  徐爱功  张兆南  吴探诗  李国明 《全球定位系统》2014,(1):37-41

介绍了精密单点定位的基本原理及常用组合量,利用日本东京海洋大学研发的开源软件RTKLIB进行静态精密单点定位数据处理,采用事后、快速、超快速三种星历及钟差产品对某IGS站单天观测值进行解算,并将处理结果和准确值对比。结果表明事后和快速产品单天解收敛曲线基本一致,最终收敛值 X、Y 、Z三个方向偏差在4 cm左右,完全满足一般精度要求的工程需要;采用超快速产品Y 方向上偏差较大,表明超快速产品对该软件的定位精度有一定的影响。  相似文献   

基于POI数据的城市建筑功能分类方法研究     

曹元晖  刘纪平  王勇  王良杰  吴文周  苏奋振 《地球信息科学学报》2020,22(6):1339-1348

对建筑物进行建模与分析是智慧城市建设的重要任务之一。将城市中数量庞大的建筑物按功能分类,辅助认知城市内部空间结构,对政府部门开展人口估计,土地管理,城市规划等工作具有重要意义。本文以蕴含丰富语义信息的兴趣点（POI, Point of Interest ）作为主要信息源,针对POI分布稀疏导致大量建筑物无法识别出功能的问题,改进了传统的城市功能区定量识别方法。该方法为建筑物内部及周边一定区域范围内的POI赋予反距离权重,通过计算不同类型POI的加权频数密度比例来识别建筑物功能类型。文中以北京市西四环中路附近5000多栋建筑物为例进行实验验证,实现了将目标区域内的建筑物按功能类型划分为居住、商业、公服和3种混合类型,识别率达93.04%,与人工判别的结果对比得出总体分类精度达91.18%。该方法采用易于获取的互联网POI数据,可以实现大范围建筑物功能类型的快速自动化识别,丰富了城市建筑模型语义属性,扩展了POI数据的应用范围。  相似文献