Impacts of confining pressure and safety thickness on water and mud inrush in weathered granite

Abstract

Due to the strong disintegration and water erosion of completely weathered granite, water and mud inrush disasters are apt to take place in this zone during underwater tunnel construction. The pore, compactness, seepage path length, fracture geometries and their interconnections for water and mud transfer are strongly influenced by confining pressure and waterproof-resistant slab safety thickness. In order to inspect the influence, a series of experiments based on a self-designed testing system and non-Darcy testing method were performed. The results indicated that the water and mud inrush evolution increased with the increase of confining pressure and decreased with the increase of safety thickness. In particular, the confining pressure mainly influences the initial evolution stage, and a critical safety thickness to prevent water and mud inrush is obtained. Besides, the non-Darcy testing method results shows that the water and mud inrush evolution affects the influence of non-Darcy flow. For example, while the safety thickness was smaller than the critical value, the evolution was large and unstable and its behavior transferred into nonlinear. In this case, the flow changed to non-Darcy flow.     

深水地震资料速度分析方法与应用

深水地震资料受水深、海况、地貌、地质情况以及采集等因素的影响,速度分析同时也受各向异性、水深变化、噪音干扰严重、照明分布不均等特征的影响,因此,常规速度分析方法不能满足深水地震资料速度分析的需要。针对这些问题,采取运用高密各向异性双谱速度的分析方法拾取高密度速度和各向异性参数。该方法应用于南海多个深水区地震资料速度分析,取得了良好的应用效果。     

Correlation analysis and partial least square modeling to quantify typical minerals with Chang＇E-3 visible and near-infrared imaging spectrometer＇s ground validation data

In 2013, Chang＇E-3 program will develop lunar mineral resources in-situ detection. A Visible and Near-infrared Imaging Spectrometer （VNIS） has been selected as one payload of CE-3 lunar rover to achieve this goal. It is critical and urgent to evaluate VNIS＇ spectrum data quality and validate quantification methods for mineral composition before its launch. Ground validation experiment of VNIS was carried out to complete the two goals, by simulating CE-3 lunar rover＇s detection environment on lunar surface in the laboratory. Based on the hyperspectral reflectance data derived, Correlation Analysis and Partial Least Square （CA-PLS） algorithm is applied to predict abundance of four lunar typical minerals （pyroxene, plagioclase, ilmenite and olivine） in their mixture. We firstly selected a set of VNIS＇ spectral parameters which highly correlated with minerals＇ abundance by correlation analysis （CA）, and then stepwise regression method was used to find out spectral parameters which make the largest contri- butions to the mineral contents. At last, functions were derived to link minerals＇ abundance and spectral parameters by partial least square （PLS） algorithm. Not considering the effect of maturity, agglutinate and Fe~, we found that there are wonderful correlations between these four minerals and VNIS＇ spectral parameters, e.g. the abundance of pyroxene correlates positively with the mixture＇s absorption depth, the value of absorption depth added as the in- creasing of pyroxene＇s abundance. But the abundance of plagioclase correlates negatively with the spectral parame- ters of band ratio, the value of band ratio would decrease when the abundance of plagioclase increased. Similar to plagioclase, the abundance of ilmenite and olivine has a negative correlation with the mixture＇s reflectance data, if the abundance of ilmenite or olivine increase, the reflectance values of the mixture will decrease. Through model validation, better estimates of pyroxene, plagioclase and ilmenite＇s abundances are given. It is concluded that VNIS has the capability to be applied on lunar minerals＇ identification, and CA-PLS algorithm has the potential to be used on lunar surface＇s in-situ detection for minerals＇ abundance prediction.     

塔里木盆地古近纪岩相古地理

古近纪是塔里木盆地由海向陆转化的时期。当时该区的海侵来自研究区西侧的古地中海分支,物源则主要是盆地北部的南天山以及南部的昆仑山,沉积中心在库车坳陷西部以及塔西南坳陷带的西部。古新世-始新世早期（库姆格列木群沉积期）在盆地北部库车坳陷发育砾岩、砂岩、碳酸盐岩及膏盐岩,沉积环境有滨岸、漏湖、潮坪及扇三角洲等,塔西南坳陷以碳酸盐岩和膏岩为特征,从东到西发育开阔台地、近岸局限台地、蒸发盐台地、辫状河三角洲环境等,二者之间即在塔北隆起及北部坳陷带位置为宽阔的古隆起区。始新世晚期-渐新世（苏维依组沉积期）整个盆地以滨浅湖为主,发育粉砂岩与泥岩互层沉积,塔西南坳陷虽然仍发育多个海相层,但海水的影响明显比始新世早期弱,当时主要古地理单元有海湾渴湖、滨浅湖、扇三角洲和辫状河三角洲。总体上,塔里木盆地在古近纪经历了早期以扇三角洲为主的浅水环境到晚期的滨浅湖及海湾溻湖环境,古近纪研究区的古气候以热带-亚热带的干旱气候为主。     

中国地震历史资料的信息开发与利用

本文对全国历史地震资料的有用信息作了进一步的开发和利用，按统一方法处理了大量有感以上地震的文字记载，确字每个独立地震的时间与地点；分区求得地震的有感区长半径与震级的关系式；确定了历史有感地震的最低震级为４；取得了８０００余次有感地震垢基本参数；用等震线测定了巨大地震的参数；将有感强震目录统编成全国与几个大区Ｍ≥４．０地震目录，按《地震学地震预报实用程序系统》（ＥＰＳＥＩＳ）的格式要求建库；同时编制     

辽西地区中生代义县旋回火山活动特征分析

辽西地区广泛发育中生代火山岩,其中以义县旋回火山岩最为发育。本文在对辽西地区义县旋回火山岩微量元素地球化学特征研究的基础上,认为义县旋回火山岩具有同源性质,由壳幔混溶物质作用于统一的火山活动过程中产生。     

关于GeoMedia Professional坐标系统定义问题的探讨

介绍了GeoMedia Professional软件在油田地面工程数字化工作中的应用,并针对设置工作空间、数据库、特征类的坐标系统时容易混淆的问题,及该问题引起的不同数据库之间的坐标系统不一致,以及一个数据库中个别特征类的坐标系统参数不正确的情况进行了分析,同时总结了操作过程中需要注意的问题及解决方法。     

干旱荒漠区植被覆盖变化的遥感监测分析

多期的遥感数据可以用来分析干旱荒漠区植被的空间分布格局和变化特征。本文以1989、2000和2007年3个不同时相的Landsat TM/ETM+影像为数据源,利用线性光谱混合分析和RGB彩色合成法构建一个研究框架,对古尔班通古特沙漠西缘进行植被信息的提取和变化监测分析。在混合像元分解过程中,通过多种方法选择端元,比较...     

基于GPT2w模型化加权平均温度反演可降水量

提出一种基于GPT2w模型化加权平均温度反演大气可降水量的方法,并分析附加系统偏差改正的模型化加权平均温度对可降水量的影响。结果表明,基于GPT2w模型化加权平均温度反演的大气可降水量的精度与基于Bevis公式计算的加权平均温度反演的大气可降水量的精度相当;对GPT2w模型化加权平均温度进行系统偏差改正后,大气可降水量的精度有一定改善,但改善率不到1%。     

地震孕育体源流变模型(三)--前兆场

在三维流变介质体源孕震模型的粘弹性位移场与应变场理论基础上,建立了流变介质体源孕震模型的前兆场理论解,导出了流变介质中任意一点（x,y,z）的地倾斜、地下水位、电阻率的粘弹性解析解,并对地电阻率的应用作了初步分析,为地震孕育过程中前兆分析提供了一定的理论基础.