共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
蒙脱石晶体胀缩规律及其与基质吸力关系研究 总被引:8,自引:0,他引:8
研究了饱和、非饱和膨胀土中对膨胀土工程力学特性有重要作用的胀缩性矿物──蒙脱石晶体的膨胀、收缩变化规律, 将蒙脱石晶体中晶层之间的各种作用综合归纳为收缩和膨胀两种作用势, 并通过实验研究和分析, 给出了膨胀势和收缩势随层间距变化的表述公式, 以及非饱和膨胀土基质吸力随层间距的变化规律, 为进一步研究膨胀土的胀缩机理和非饱和土的基质吸力势提供了一种新的理论基础和研究途径. 相似文献
3.
为解决在膨胀土山区修建机场时跑道地基处理的问题,以安康地区膨胀土为研究对象,在对现行石灰改良膨胀土施工控制参数常用方法分析的基础上,进行膨胀土及石灰改良膨胀土的膨胀性能和强度的相关试验。研究结果表明:随着石灰掺量的增加,最优含水率增大,最大干密度减小,胀缩潜势呈降低趋势,石灰掺量与最大干密度呈非线性关系,在石灰掺量达到9%时有荷膨胀率变化的规律性很强;相同石灰掺量改良土的CBR与击实功、含水量等因素有关,并不随着压实系数增加而增大。掺加石灰的比例对石灰改良膨胀土的强度增长影响较大,石灰掺量9%时的CBR值明显大于其他掺量;相同压实系数下石灰掺量3%和6%改良膨胀土的压缩性比较接近,石灰掺量增加到9%时其压缩性明显降低。结合试验结果,提出用石灰改良膨胀土对跑道进行地基处理,并以膨胀性指标作为主要控制指标、强度指标作为验证指标来确定施工参数。 相似文献
4.
5.
为了研究浅层膨胀土的细观结构在湿干循环过程中的演化规律,研制了可以进行CT扫描的CT-固结仪。在不同压力作用下对南阳膨胀土的原状样及其重塑土样进行多组多次湿干循环试验,并对每次烘干和增湿稳定后的试样进行CT扫描,跟踪观察湿干循环过程中试样的细观结构变化。结果表明:在湿干循环中,土样的膨胀量和收缩量都比较大,经历三次湿干循环之后,相同饱和度下土样体积基本不再变化;增湿和干燥都能使原状膨胀土及其重塑土的结构损伤,第一次烘干之后,土样即产生明显裂隙;随着湿干循环次数的增加,土样裂隙继续开展,土样结构损伤发生累积;上部荷载对裂隙开展有一定抑制作用,并影响裂隙的发育和裂隙网络的形状;原状膨胀土的裂隙围绕第一次形成的主裂隙发育,而重塑膨胀土的裂隙呈龟背状或辐射状;原状膨胀土及其重塑土在湿态(饱和度Sr=85%)时的CT数ME值均较干态(饱和度Sr=25%)时的ME值大;湿态和干态的ME值均随湿干循环次数呈近似线性变化,前者的坡度比较平缓,后者则较陡;基于CT数据定义了膨胀土的细观结构参数,提出定量描述湿干循环过程中膨胀土细观结构参数与试样饱和度、湿干循环次数及所受荷载的数学表达式,预测结果与试验资料比较接近。 相似文献
6.
膨胀土胀缩等级划分的新途径 总被引:3,自引:0,他引:3
膨胀土胀缩等级的划分与施工安全及工程经济核算直接相关,目前对膨胀土等级的划分还处于研究阶段,有的采用胀缩总率eps,有的采用自由膨胀率F_s、液限W_t、膨胀压力P_p等指标,划分方法不同结果也不同。本文从模糊数学角度,对分类中常用的几个因素进行综合评判,进行胀缩等级的划分 相似文献
7.
8.
9.
通过钻探、标贯、取样、波速测试、室内岩土力学分析、化学实验,对塔河油田2-10号油区地面工程建设基础进行了工程地质勘察、地下水条件分析。结果表明,塔河油田膨胀土属于盐渍土类型,其对建筑物基础有危害性,膨胀土场地建筑物基础埋深不能小于1.5m。提出了防治措施,为塔河油田地面建设工程基础防治提供了科学依据。 相似文献
10.
大气作用下膨胀土地基的水分迁移与胀缩变形分析 总被引:2,自引:0,他引:2
运用土体渗流和蒸发理论,建立了大气-非饱和土相互作用模型;以现场观测的气象数据作为边界条件,进行了地基土中水分迁移的数值模拟,得到了大气作用下地基土体含水量的动态分布规律。计算结果表明,地基土中含水量变化幅度随深度增加而递减,3.5 m深度以下土体的体积含水量基本不变,从而确定了南宁地区膨胀土地基的大气影响层深度为3.5 m。在此基础上,结合已有膨胀土胀缩性指标的干湿循环效应研究成果,提出了一种同时考虑干湿循环效应和1.0 m深处含水量变化的膨胀土地基胀缩变形计算方法,通过算例将该法与传统方法进行比较,结果显示该法更加符合工程实际。 相似文献
11.
应对巨大地震的应急流动观测系统 总被引:3,自引:0,他引:3
通过“十五”数字地震观测网络项目建设,目前。我国的地震观测系统和地震观测信号传输几乎完全依赖于公共通讯网络。但是,大地震常常严重破坏公共通讯系统,应对巨大地震的流动观测系统就提到迫切的日程。2007年,通过采用无线竞带接入技术,结合中国地震局数字地震观测网络技术,初步建成了应对巨大地震的应急流动观测系统,并在汶川地震现场观测初期发挥了重要作用。 相似文献
12.
2001年昆仑山口西8.1级特大地震发生后,至2006年连续5年,地震界对中国大陆地震形势判定与地震活动实况相差甚大,这是为什么?本文揭示了我国中期地震预报的真实水平和其本质原因,系统地阐述了我国中期地震预报存在的问题,提出了提高中期地震预报水平的主要出路和途径。 相似文献
13.
CUI-YING ZHOU YUAN-QING ZHU HONG-WEI WANG KAI-LI LIANG PING LI AI-XIANG GUO 《地震学报(英文版)》1999,12(2):232-237
parameters integrated predictionIn current earthquake prediction, seismological method is considered the first choice. According to rough statistics, there are over 100 seismological parameters used in earthquake prediction in China. That a great number of parameters could be chosen is more convenient, but also causes a lot of troubles at the same time. It is more difficult to decide which one is better among them. In the practical key problem and the 'Eighth Five-Year Plan' key problem on short-period earthquake prediction sponsored by China Seismological Bureau, most of the parameters have been evaluated on efficiency, but it is still not easy to decide which one can be given the priority and which one should be discarded, because the adopted data, the sample numbers and the evaluation criteria were not always consistent in these researches. Therefore, the first problem which the earthquake predictors are facing is how to select the best one from so many seismological parameters. In the past, most of the parameters were used in the seismic cases, but never used in the zone where no strong earthquakes occurred, in this way it is impossible to cast away 'false abnormality'. Furthermore, as the process of seismogeny is nonlinear and complicate, the non-uniqueness and uncertainty of the development process make the seismic precursors different in time, place and earthquake, which often causes false prediction when a single parameter is used. In order to solve the problem better, this paper attempts a new method comparison screening, to select seismological single parameter and to collect a comprehensive seismological parameter on this basis. The basic procedure may be summarized as follows: on the basis of reasonable normalization of various parameters, quantitative comparison screening of some basic seismological parameters by using the two sorts of samples from 'large-magnitude seismic zone' and 'no large-magnitude seismic zone' in North China is conducted, to obtain 'seismic abnormality' and 'aseismic normality' indexes, and then to synthesize these indexes with weighting method according to the strength of the earthquake information to obtain a integrated prediction index which is universal to predict the earthquakes in North China, and meanwhile develop a new seismological prediction method which is abbreviated as SQIP (seismological quantitative integrated prediction method). 相似文献
14.
徐元耀 《地震地磁观测与研究》1993,14(3):33-36
对大丰地震台井下摆1983-1992年的观测资料统计分析,发现井下摆测定的震级普遍低于江苏省地震局台网的平均震级,且和震中距有一定的关系。通过对震级偏差的计算得出大丰台的台站校正值。同时,对偏差的原因进行了探讨。 相似文献
15.
16.
Observations on an Early Quaternary slope deposit in the Massif Central indicated that the texture and mineralogy of this deposit have been seriously altered by post-depositional subsurface weathering. Analyses of clay fractions and water samples show that the montmorillonite present is a stable mineral in this environment and is, and has been, newly formed. As shown by water analyses from nearby sites, the chemical environment is strongly dependent on local factors. Consequently it can be seen that great care should be taken firstly in correlating different slope deposits on the basis of texture and clay mineralogy and secondly in using these parameters as (paleo) climatic indicators. 相似文献
17.
地震烈度衰减关系统计方法的探讨 总被引:2,自引:0,他引:2
在地震学和地震工程学的研究中,地震烈度衰减关系的研究和应用日益受到重视。本文从在等烈度外包线上如何取烈度值,烈度衰减曲线的头尾处理,R0值的选取,衰减公式的偏差这四个方面对目前广泛使用的地震烈度衰减关系的统计方法作了分析和探讨,指出了这些方法中存在的不足,并提出了改进的建议。 相似文献
18.
The seismological observation system in China has experienced rapid development over the Tenth Five-year Plan period. China Earthquake Administration (CEA) has completed the establishment of China digital seismological observation network. CEA has accomplished analog-to-digital conversion of the existing seismological observation systems and set up a number of new digital seismic stations. This indicates full digitization of seismological ob-servation in China. This paper presents an overview of the scale,layout principle and major functions of the up-dated national digital seismograph network,regional digital seismograph network,and digital seismograph net-work for volcano monitoring and mobile digital seismograph networks in China. 相似文献
19.
By taking moderate-strong earthquakes in South,North and West China as the research subjects and taking into consideration the fault strikes in these regions,this paper selects 8 kinds of seismology indexes with clear physical significance and strong independence to carry out spatial scanning of the parallel,vertical and oblique slip of fault along the fault strike.Based on the size of correlation coefficients between the scanning curve and source region curve we quantitatively analyze the difference between scan results among different slip modes and study the impact of fault strike in different tectonic divisions on scanning results and variation rules of seismological parameters.The results show that not only does the change of spatial parameters have a great influence on seismological parameter scanning,but so does the fault strike in the source region.This paper presents the optimum condition parameters with least spatial influencing scanning scope for different magnitude seismology indexes and analyzes the possible influence of fault strike on seismological parameter scanning results. 相似文献
20.
在用FOXBASE,TurboBasic等软件开发的测震编目系统的基础上,把GIS技术中处理空间信息的一些独特优点应用到测震编目系统中,建立了以GIS工具软件Mapinfo为开发平台的图形绘制查询分析配套系统。实现了与测震编目系统的数据对接。使对接后的系统在可视化查询、分析计算、图形制作、Bufer分析、显示输出等方面有了很大的改进。整个系统具有良好的用户界面,有较强的数据兼容性和模块扩充性。 相似文献