GPS测量技术在锡山市地面沉降研究中的应用

通常研究认为, 苏锡常地区超量开采地下水是产生地面沉降最主要的因素之一。锡山市地下水开采十分强烈, 其地面沉降灾害也最为严重。为了有效地分析研究地面沉降的发生发展过程, 必须获取一定时间间隔内的地面沉降实测值, 全球定位系统 (GPS)就是一种既经济又高效的测量手段。本文在简要介绍了锡山市地质、水文地质及地下水开发利用情况的基础上, 重点阐述了运用GPS测量技术对锡山市地面沉降进行首次实测的情况, 并对其测量结果进行了系统分析, 最后对锡山市地面沉降的发展历史和现状进行了初步讨论。     

地球空间信息科学之刍议

地球空间信息科学是地球科学、空间科学和信息科学交叉渗透发展的结果。它由地球空间信息理论、地球空间信息技术和地球空间信息应用等三个部分组成。它的主要研究方向是从空间信息流的角度揭示和认识地球系统，特别是地球表层系统的现象和过程，地球各圈层相互作用的时空特征。地球空间信息科学在国家和区域的可持续发展及资源、环境和人口的协调发展中具有广阔的应用前景。     

人工地震横波地质勘察——查明复杂、疑难地质问题的新方法

人工横波地震是工程物探的一种新技术，但由于理论上存在一些误区，在工程实践中给地质解释带来一定困难。正确理解和计算横波波速是解决这个问题的首要任务，利用多次叠加时动校正的速度能量团计算横波速度比较可靠，该技术的应用已成功地解决了一些疑难复杂地质问题。准确的横波波速计算可使横波勘探得到更好地推广和应用，为工程设计和建设提供可靠的地质资料。     

Observation of isotopes in the water cycle—the Swiss National Network (NISOT)

The Swiss National Network for the Observation of Isotopes in the Water Cycle (NISOT) includes eleven precipitation, seven surface water (river) and three groundwater stations, where tritium, deuterium and oxygen-18 are monthly measured in composite samples. The network provides a good overview of the characteristic isotope signatures in recharge waters in Switzerland and of the relations between isotopes and altitude, orography and the amount of precipitation. Mixing of air water vapour and surface waters can be observed along a NW/SE cross section through the Alps. With increasing length of the data series, the network provides a valuable contribution for national and international scientific and practical applications in surface and subsurface hydrology, climatology and biology. The Swiss Geological Survey at the Federal Office for Water and Geology operates the isotope network within the legal framework of the Federal Law on the Protection of Waters and guarantees quality, access and distribution of the isotope data.     

提高PHSJ-4型PH计观测质量的探讨

PHSJ-4型PH计是我局第一台高精确度的PH计,应用到实际观测过程中,遇到许多影响观测质量的具体问题。本文针对PHSJ-4型PH计使用过程中遇到的乱码、测值突跳、电极老化快、合理分辨率的确定、温度干扰因素的控制等问题展开分析,做了大量的条件实验,结合该仪器的工作原理以及PH值所遵循的化学原理,指出要提高和保障观测质量,观测时必须做到如下几点:调节观测参数时用指腹轻按,出现局部黑屏、乱码现象可采用关机后重新开机解决;电极一定要浸泡在KCL保护液中,观测完毕清洗电极后一定要用滤纸把残余的蒸馏水擦干后再授泡在KCL保护液中以免降低电极保护液的保护功效,延长电极的寿命;水样要达到室温时才能进行观测;合理分辨率应设置在0.01PH档。     

Microscopic observation and contact stress analysis of granite under compression

To study the damage process of microscale to macroscale in coarse-grained granite specimen under uniaxial compressive stress, we have observed micro-damage localization and propagation by using a newly developed experimental system that allows us to observe the damaging process continuously.

The results showed that pre-existing microcracks lead to macroscopic shear fracture through the damage development process. The mechanism of micro-damage initiation in a granite specimen under uniaxial compressive stress may be considered for two cases. One is that two grains such as quartz and feldspar contact each other in the same direction as the axial stress, and the other is that a biotite grain inclined to the axial stress direction is surrounded by feldspar grains. The homogenization theory was applied to verify numerically the micromechanics of stress-induced damage in the mineral contacts. Local stress distribution in the periodic-micro structure was also calculated by the homogenization theory. It is shown that this analysis, which takes into account the initial state of the specimen, is well adapted to the behavior of two grains for which microcracking is the fundamental mechanism of damage.     

Particle orientation and its influence on the mechanical behaviour of isotropically consolidated reconstituted clay

The behaviour of naturally occurring geological materials such as clay and sand depends on many factors. For example, stresses, strains, previous stress history, mineralogy and the depositional environment all contribute in some degree to a characteristic that all natural soils share, namely “structure”. The structure of clay, or more generally, the microstructure of microscopically sized clay mineral particles, is just as important as the many other parameters that are used to quantify the performance of clays. This paper examines the microstructure that results from the particle arrangement brought about during reconstitution in the laboratory and considers its relevance to the resulting stress–strain behaviour.

Samples of reconstituted kaolin clay were produced using two different procedures. In the first series of tests, kaolin slurry was simply isotropically compressed in one increment. In the second series, the slurry was first isotropically compressed to a low pressure and then completely remoulded. This was followed by isotropic compression to the same pressure as the other series. Specimens were taken from the two series of samples, reconsolidated at various isotropic pressures, and sheared under undrained conditions.

Scanning Electron Microscope (SEM) images indicated that the monotonically compressed samples (Series 1) exhibited an anisotropic microstructure that was distinct from the remoulded (Series 2) samples. Significant differences were also found in the consolidation and stress–strain characteristics of the samples produced in the two series.     

福建省长诏带重力复测资料精度分析

本文利用长诏带十二期LCR -G重力仪复测资料精度情况 ,对在施测中存在着问题 ,误差来源情况 ,结合重力仪的构造特点进行分析。认为影响观测精度主要来源有二类 ,一类是客观因素 ,如振动、温度、气压等因素 ;另一类为主观因素 ,如观测方法 ,气泡置平等。如果在今后的工作中更注意这些干扰因素 ,可进一步提高成果精度     

基于可靠度理论的变形监测必要精度指标的确定方法

以结构安全度为约束条件，将结构的变形测量误差视为等效荷载纳入荷载组合，获取荷载最不利组合状态下的极限变形△；从统计力学角度界定变形体的允许变形，必要测量精度指标等参数。