共查询到19条相似文献,搜索用时 187 毫秒
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在对山西大同市区3个主要地貌单元共72个钻孔的剪切波速资料分析整理的基础上,利用指数形式的剪切波速与深度经验公式,对测点较多的粉质黏土、粉土、粗砂三类土层的剪切波速Vs与土层深度H的关系进行统计回归,并将实测剪切波速值与利用上述统计结果得到的预测值进行对比检验,结果表明,分地貌单元各类土层的Vs-H经验关系是可靠的,符合当地岩土特征,可用于对该地区地层剪切波速进行推测。 相似文献
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基于杭州市丰富的场地钻孔剪切波速资料,采用3种常见的剪切波速与埋深回归分析模型,分析杭州地区5类常规土在场地分类和场地未分类情况下的最优拟合公式和预测范围,并对推荐模型进行可靠性验证,对常规粉质粘土和粉砂进行地区差异性分析。研究结果表明:本文推荐的剪切波速与埋深关系公式具有良好的可靠性;地区、岩土类型和预测深度均对剪切波速与埋深关系模型的可靠性产生显著影响,故应用时应优先选用本地区统计模型,如若未有,则需根据已有资料,对选用模型进行岩土类型和适应预测深度范围验证,以保证所选模型的可靠性;受地区、岩土类型和预测深度的影响,考虑场地分类并不一定提高统计模型的预测精度,在实际工程应用中具有不确定性。 相似文献
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通过对山西长治市区41个钻孔柱状和剪切波速资料的整理分析,利用剪切波速与深度的指数式经验公式,对土层剪切波速Vs与土层深度H间的关系进行统计回归。经对比检验得出,土层Vs-H统计关系符合本地岩性特征。 相似文献
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《地震地质》2016,(4)
一般认为土层剪切波速与埋深关系的回归公式主要用于对当地土层剪切波速值的初步估计。为了提高钻孔波速测试数据的应用价值,基于土层剪切波速与埋深关系的主要数学模型及其拟合参数,推导了场地覆盖层厚度计算公式、等效剪切波速计算公式和时深转换中反射波组埋深计算公式。以河南省长垣县场地为例,采用上述新公式计算获得的场地覆盖层厚度值、等效剪切波速值可满足工程需要。并提出应用这些新公式的步骤为:1)依据场地相关资料划分地震工程地质单元;2)对同一个地震工程地质单元内的钻孔波速测试数据进行统计分析,综合判别和选择土层波速与埋深统计关系的数学模型及其拟合参数;3)将选择的数学模型的拟合参数分别代入上述的新公式,即可分别获得场地覆盖层厚度、等效剪切波速或地层反射波组埋深。 相似文献
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收集和田市土层钻孔剪切波速实测数据,按照地貌单元划分,按不同岩性分别采用线性函数模型、一元二次函数模型及幂函数模型等三种模型进行土层剪切波速与土层埋深的统计回归分析,给出拟合参数和拟合优度R2,从而得到和田市各工程地质单元各类土层剪切波速与土层埋深关系公式。并对统计回归分析结果进行了显著性检验,此基础上计算出场地覆盖层厚度计算值,将土层剪切波速预测值与实测值、覆盖层厚度计算值与实测值进行对比,验证统计回归关系式的合理性和适用性。结果表明,统计分析得到的和田市城区各工程地质地貌单元各类土层剪切波速与土层埋深关系公式较为准确可靠。 相似文献
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通过对西安市3个主要地貌单元共309个钻孔剪切波速资料的分析整理,采用指数和线性拟合两种方法对测点较多的细砂、中砂、粗砂、黄土、粉质粘土、古土壤、卵石等土类的剪切波速VS与土层深度H的关系进行统计回归,得到其经验关系式;将实测剪切波速值与利用上述统计结果得到的预测值进行对比检验,两者差别不大。说明区分地貌单元和各类土层的VS与H经验关系可靠且符合当地岩土特征,可用于西安地区一般建筑的工程勘察与地震安全性评价工作。 相似文献
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APPLICATION AND STATISTICAL ANALYSIS OF RELATIONSHIP BETWEEN SHEAR WAVE VELOCITY AND DEPTH OF SOIL-LAYERS 下载免费PDF全文
The shear wave velocity is one of the important parameters in seismic engineering.The common mathematical models of relationship between shear wave velocity and depth of soil-layers are linear function model,quadratic function model,power function model,cubic function model,and quartic function model.It is generally believed that the regression formulae based on aforementioned mathematical models are mainly used for preliminary estimation of the local shear wave velocity.In order to increase the value of test data of wave speed in boreholes,the calculation formulae for the thickness of ground cover layer are derived based on the aforementioned mathematical models and their fitting parameters.The calculation formulae for the mean shear wave velocity of soil-layers are derived by integral mean value theorem.Accordingly,the calculation formulae for the equivalent shear wave velocity of soil-layers are derived.The calculation formulae for the depth of reflective waves in time-depth conversion of the reflection seismic exploration are derived.Through the statistical analysis of test data of shear wave velocity of soil layers in Changyuan County,Henan Province,regression formulae and their fitting parameters of aforementioned mathematical models are obtained.The results show that in the determination of the quality of these regression formulae and their fitting parameters,the adjusted R-square,root mean square error and residual error,the matching on the statistical range between the geometry of function of mathematical models used and the scattergram of the measured data,the application purpose and the simplicity of the regression formulae should be considered.With the aforementioned new formulae,the results show that the calculated values of equivalent shear wave velocity of soil-layers and thickness of ground cover layer meet the engineering needs.The steps for statistics and applications of the relationship between shear wave velocity and depth of soil-layers for a new area are as follows:(1) Analyze the relevant data about the site such as the drilling and wave speed test data,etc.and divide the site into seismic engineering geological units;(2) In a single seismic engineering geological unit,make statistical analysis of the data of borehole wave speed test,comprehensively identify and select mathematical models and their fitting parameters of the relationship between shear wave velocity and depth of soil-layers;(3) Substitute the selected fitting parameters into the formulae,based on their mathematical models for the thickness of ground cover layer,or the equivalent shear wave velocity of soil-layers,or the depth of reflective wave,then the thickness of ground covering layer,equivalent shear wave velocity,and depth of reflective wave are obtained. 相似文献
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工程抗震工作需要掌握各层土的剪切波速度资料,以便进行地震危险性分析和场地震害小区规划等项工作。采用瑞利波法进行岩土力学特性指标测定,通过实际性能应用表明该方法是简便易行的。 相似文献
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Based on the empirical Gardner equation describing the relationship between density and compressional wave velocity, the converted wave reflection coefficient extrema attributes for AVO analysis are proposed and the relations between the extrema position and amplitude, average velocity ratio across the interface, and shear wave reflection coefficient are derived. The extrema position is a monotonically decreasing function of average velocity ratio, and the extrema amplitude is a function of average velocity ratio and shear wave reflection coefficient. For theoretical models, the average velocity ratio and shear wave reflection coefficient are inverted from the extrema position and amplitude obtained from fitting a power function to converted wave AVO curves. Shear wave reflection coefficient sections have clearer physical meaning than conventional converted wave stacked sections and establish the theoretical foundation for geological structural interpretation and event correlation. "The method of inverting average velocity ratio and shear wave reflection coefficient from the extrema position and amplitude obtained from fitting a power function is applied to real CCP gathers. The inverted average velocity ratios are consistent with those computed from compressional and shear wave well logs. 相似文献
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基于广西柳州地区地震安全性评价中实测所获的钻孔资料,利用线性模型、幂函数模型和二次函数模型分别对该地区土层剪切波速与埋深之间的相关性进行了拟合分析,通过对比发现幂函数模型为二者间相关性拟合的最优选择,同时探讨了土体状态对二者相关性的影响。结果表明:除人工填土外,柳州地区内常见土层剪切波速与埋深之间具有较强的相关性,区域性对其相关性也具有影响。最后以实测钻孔为例,验证了本文模型的预测精度和可靠性,而且模型的预测精度可以通过区分土体状态得到明显提高。 相似文献
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