地面地质横剖面在川东高陡构造地震资料处理解释中的作用

川东高陡构造具有同心褶皱的特点，地下构造的脊点与地面构造的形态具有一定的规律性。根据这种规律设计出的地质物理模型，不但可以帮助处理好构造顶部和轴部的地震资料，还能使地震剖面的地质解释更加合理。本文中的地质模型就是依据地面地质横剖面设计的，文中用实例说明了地面地质横剖面在地震资料处理和解释中的重要作用。

隧道断层地面地质调查技术及应用

在隧道施工中,经常遇到的不良地质构造即为断层,它是造成隧道塌方的主要原因之一,也是涌突水、煤与瓦斯突出,甚至岩爆等诸多隧道施工地质灾害产生的原因。由于在设计阶段地质勘查工作的精度有限,往往造成断层位置不准确甚至遗漏,因此在施工阶段,在设计勘察资料的基础上,采取地面地质调查手段对断层进行修正和完善显得非常重要。在总结前人施工经验的基础上,介绍了安康至陕川界高速公路MC2合同段特长隧道毛坝1号隧道在断层施工和地面地质调查中的实践经验,论述了地面地质调查技术在断层施工预防和治理方面的重要性。

断层性能、地面地质和三维速度模式之间的关系

对围绕着加利福尼亚的五个大地震地区的三维 P 波速度模式的研究,导致了对断层性能与在易震深度处断层的岩石的介质特性之间关系的认识,高力矩释放地区显示出与高地震速度相关,而破裂的初始或破裂的终止可能与低地震速度相联系。这种关系可以理解为什么断层可以被分割为各自独立破坏的段,并表明我们能够增进对预测地震以及强地面运动的能力的认识。断层显示的特性从无震蠕动到大地震引起的脆性破裂。由于沿着某个断层长度的这些变化,可以把断层分割为各自独立破坏的段落。为了研究支配着这些变化的机制,对围绕着加利福尼亚5个中强地震的区划,我们确定了该地区的三维(3D)P 波速度(V_P)模式。

水溶开采诱发盐矿地面沉降机理分析及防治措施

随着我国国内采用水溶法开采盐矿的普及,地面沉降地质灾害屡屡发生。因盐矿地面沉降一般具有持续周期长、影响规模大、破坏性大、突发性强、反复发生、发生前后通常伴随地面冒卤等特点,总结后发现采空区造成溶腔顶板失稳、岩石节理裂隙或断层发育、溶腔顶板岩体承载力低是水溶开采诱发盐矿地面沉降的3种主要因素。主要从事前预防、事中控制以及事后补救这3个方面提出了相关的地面沉降治理措施建议。

地面塌陷地质灾害应急处置技术方法研究

随着社会的发展,人类建设工程日益增多,导致原本平衡的自然地质受到破坏.在岩溶发育的喀斯特地貌区,受强降雨、地下水作用及人类活动等不利因素影响下,造就了地面塌陷地质灾害的形成.同时破坏了地质环境,给人民的生命财产造成威胁和损失.

钻孔地质雷达技术在水文与工程地质中的应用分析

目前,钻孔雷达技术在国外已被广泛应用于各领域,但相对于我国来说还是一种新技术。由于钻孔地质雷达可以探测到比地面地质雷达更深的地质目标体,因而可广泛应用于水文地质与工程地质领域,用来探测深部的断层、裂隙及破碎带等不良地质体。本文首先概述了目前国内外钻孔雷达在水文地质与工程地质领域的应用和研究情况;然后通过实例详细分析了该技术在实际工作中的应用效果;最后总结了钻孔雷达技术在水文地质与工程地质方面的应用优势,并指出了钻孔雷达技术现阶段存在的一些问题及其未来在我国的发展方向。

斜坡坡面地质灾害SNS柔性防护系统概论

在简单分析评价国内现有坡面地质灾害防治现状的基础上 ,介绍了以钢丝绳网为主要构成材料的 SNS( Safty Netting System)主动覆盖和被动拦截柔性防护系统的基本构成和功能特征 ,从而阐明了该项新技术在防护功能、标准化设计与施工作业以及对复杂地形的适应性和安全可靠性等方面的技术经济优势。

基于BIM的道路地质地面信息模型构建及应用

基于BIM的道路全数字三维地质地面信息模型构建是实现道路工程BIM动态设计的关键。以北京市平谷区黄松峪山区某道路工程为例,将道路地质地面信息导入到Civil 3D中,利用Civil 3D的点、块、曲面、实体提取等功能,构建了三维地质地面信息基础模型并在此基础之上进行综合设计,实现了基于地质地面信息的纵断面设计、土石方计算等定量分析。结果表明,该方法可以初步解决道路设计中地质地面信息储存、管理、分析以及可视化的问题,为基于BIM的道路全数字化正向设计提供支撑。

Characteristics of discontinuities in Heifangtai landslide area in Gansu,China

Loesses are widely distributed all over the world,especially in China.Meanwhile,long-term agricultural irrigation and extreme climate changes have led to frequent geological disasters in the Heifangtai area of Lanzhou,Gansu,China.Of these,landslides are one of the most frequent types of disasters that are harmful to humans and the environment.A landslide is closely related to the lithology,structure,and groundwater of the site and consists of a combination of structure units divided by discontinuities,such as faults,joints,and fi ssures.Therefore,geological surveys,engineering drilling,and trenching are typically used to identify the stratum lithology,structure,and groundwater in order to visually display underground information within a limited depth range.However,these methods have disadvantages.In particular,geological surveys can only describe geological phenomena on the surface,while the cost of drilling and trenching may be high,along with the ineffi ciency of exploration.In this research,the integrated geophysical exploration method was used to analyze the hidden joints,cracks,and other discontinuities and geophysical features of the discontinuities.The results were verified by trench exploration,and large amounts of underground information were obtained,especially the spread and distribution of discontinuities in landslide areas.Such information can be effectively used for carrying out and providing meaningful experiences and lessons in future comprehensive geophysical processing and interpretations related to the prediction and evaluation of landslides.

Technical efficiency and its determinants of the various cropping systems in the purple-soiled,hilly region of southwestern China

This study examines the technical efficiency(TE) differences among typical cropping systems of smallholder farmers in the purple-soiled hilly region of southwestern China.Household-,plot-,and crop-level data and community surveys were conducted to explore TE levels and determinants of typical cropping systems by using a translog stochastic frontier production function.Results indicate significant difference in TE and its determinants among cropping systems.The mean TEs of the rice cropping system(R),the rice-rape cropping system(RR),the rice-rape-potato cropping system(RRP),and the oil cropping system(O) are0.86,0.90,0.84,and 0.85,respectively,which are over 1.17 times higher than those of the maize-sweet potato-other crop cropping system(MSO) and the maize-sweet potato-wheat cropping system(MSW) at0.78 and 0.69,respectively.Moreover,Technical inefficiency(TIE) of different cropping systems is significantly affected by characteristics of the household as well as plot.However,the impact of land quality,mechanical cultivation conditions,crop structure,farming system,farm radius,household type,cultivated land area per capita,and annual household income per capitalon TIE vary by cropping system.Additionally,output elasticity of land,labor,and capital,as a group,is greater than the one of agricultural machinery and irrigation.Finally,when household-owned effective agricultural labor is at full farming capacity,optimal plot sizes for the R,RR,RRP,MSO,MSW,and 0 cropping systems are 1.12hm^2,0.35 hm^2,0.25 hm^2,2.82 hm^2,1.87 hm^2,and 1.17hm^2,respectively.

S/N Ratio of 4-Channel A/D Geological Radar Non-uniform Sampling Signals

Using the quantitative error probability density method we studied the S/N ratio of alternately sampled signals digitized by a 4-channel A/D. A complete expression for the S/N ratio of a 4-channel A/D non-uniform sampling signal was deduced. First we obtained an expression for the S/N ratio of a 1-channel A/D uniform sampling signal when the sampling frequency was equal to or greater than 2 times the frequency of the sampled signal. Based on the S/N ratio of a 2-channel A/D,alternating,non-uniform sampling signal,we analyzed the distribution of quantitative error using the quantitative error probability density method and the distribution convolution formula. From this the S/N ratio expression of a 4-channel A/D sampling signal was deduced. The simulation result shows that the deduced expression is correct.

Spatial Variability of Soil Organic Carbon in Different Hillslope Positions in Toshan Area, Golestan Province, Iran: Geostatistical Approaches

Accessibility to organic carbon(OC) budget is required for sustainable agricultural development and ecosystem preservation and restoration. Using geostatistical models to describe and demonstrate the spatial variability of soil organic carbon(SOC) will lead to a greater understanding of this dynamics. The aim of this paper is to present the relationships between the spatial variability of SOC and the topographic features by using geostatistical methods on a loess mountain-slope in Toshan region, Golestan Province, northern Iran. Hence, 234 soil samples were collected in a regular grid that covered different parts of the slope. The results showed that such factors as silt, clay, saturated moisture content, mean weighted diameter(MWD) and bulk density were all correlated to the OC content in different slope positions, and the spatial variability of SOC more to slope positions and elevations. The coefficient of variation(CV) indicated that the variability of SOC was moderate in different slope positions and for the mountain-slope as a whole. However, the higher variability of SOC(CV = 45.6%) was shown in the back-slope positions. Also, the ordinary cokriging method for clay as covariant gave better results in evaluating SOC for the whole slope with the RMSE value 0.2552 in comparison with the kriging and the inverse distance weighted(IDW) methods. The interpolation map of OC for the slope under investigation showed lowering SOC concentrations versus increasing elevation and slope gradient. The spatial correlation ratio was different between various slope positions and related to the topographic texture.

Relocation of Earthquakes in the Northeastern Tianshan Mountains Area and Improvement of Local 1-D Crustal Velocity Model

We apply three methods to relocate 599 earthquake events that occurred from August 2004 to August 2005 in the northeastern Tianshan Mountains area ( 85°30' ～ 88°30'E,43°00' ～ 44°40' N ) by using travel times recorded by regional seismic network and 10 portable seismic stations deployed around the Urumqi city. By comparing the reliability of different results,we determined a suitable location method,and an improved 1-D crustal velocity model of the study area. The uncertainty of earthquake location is significantly reduced with combined data of seismic network and portable stations. The relocated events are clearly associated with regional tectonics of the northeastern Tianshan Mountains area, and are also in agreement with the existence of active faults imaged by deep seismic reflection profile. The relocated seismicity discovers some potential traces of buried active faults,which need to be validated further.

Rock mechanical investigation of strata loading characteristics to assess caving and requirement of support resistance in a mechanized powered support longwall face

Longwall mining is one of the most acclaimed and widely used in underground method for coal extraction. The interaction of powered supports with the roof is the key issue in strata mechanics of longwall mining. Controlled caving of rock mass is a prerequisite pro thriving exploitation of coal deposits by longwall retreat with caving technique and support resistance has evolved as the most promising and effective scientific tool to predict various aspects related to strata mechanics of such workings. Load density,height of caving block, distance of fractured zone ahead of the face, overhang of goaf and mechanical strength of the debris above and below the support base have been found to influence the magnitude of load on supports. Designing powered support has been attempted at the different countries in different methods. This paper reviews the mechanism of roof caving and the conventional approaches of caving behaviour and support resistance requirement in the context of major strata control experiences gained worldwide. The theoretical explanation of the mechanism of roof caving is still continuing with consistently improved understanding through growing field experiences in the larger domain of geo-mining conditions and state-of-art strata mechanics analysis and monitoring techniques.

Geomorphological Features of Ancient Volcanic Terrain of Mars

The article considers geological and morphological features of a volcanic relief of a surface of a planet Mars. Effusive magmatism processes at early stages of planet crust forming come out in structure of solidified relief forms of Mars. Volcanic relief of a planet represents relic ancient line oriented forms, areal and central lava flooding. Linear forms generate shield volcanoes, chains of volcanic mountains and radial-concentric faults. This article deals with geological and morphological characteristics of the volcanic terrain of Mars. Hypsometric altitude profiles of volcanoes have been built based on the MOLA （Mars orbiter laser altimeter） of the spacecraft MGS （Mars global surveyor）. The gradient of volcano flanks has been calculated. The relative age of the volcanic terrain was estimated by the classical method of counting of the density of impact craters. Names of the volcanic landforms of Mars are given in the article in accordance with the name nomenclature system approved by the International Astronomical Union. Research results make it possible to compare the scientific and technical information about the planet and analyze the materials of satellite imagery of Mars.

Studying of Physical-Mechanical Properties of Rocks of Geological Section Considering the Influences of Recent Geodynamics

The method of determination of elastic moduli of the geological section rocks had been developed in real conditions. The method is based on application of non-classically linearized theory of elastic waves＇ propagation in the deformable media and utilization of neural networks when creating the geoseismic model. It is proposed to forecast the thin-layer model of medium by velocities of the shear waves on the base of seismic inversion of 2D profile by neural networks and geophysical well logging data. The method had been tested on materials of geophysical well logging data and 2D seismic profile related to one of the structures in the South-Caspian depression. The specific results for Poisson coefficient and elastic moduli of the third order had been obtained. The mentioned method can also be applied to forecast of other physical-mechanical properties of the medium.

Prediction of ground surface displacement caused by grouting

Ground surface displacement caused by grouting was calculated with stochastic medium theory. Ground surface displacement was assumed to be caused by the cavity expansion of grouting, slurry seepage, and slurry contraction. A prediction method of ground surface displacement was developed. The reliability of the presented method was validated through a comparison between theoretical results and results from engineering practice. Results show that the present method is effective. The effect of parameters on uplift displacement was illustrated under different grouting conditions. Through analysis, it can be known that the ground surface uplift is mainly caused by osmosis of slurry and the primary influence angle of stratum β determines the influence range of surface uplift. Besides, the results show that ground surface uplift displacement decreases notably with increasing depth of the grouting cavity but it increases with increasing diffusion radius of grout and increasing grouting pressure.

Potential Submarine Geologic Hazards at the Entrance of the Pearl River Estuary in the Northern South China Sea

The potential submarine geologic hazards were distinguished and categorized at the entrance of the Pearl River Estuary in the northern South China Sea, based upon the analysis of side scan sonar and sub-bottom profiler surveying data of about 2500 km long, in an area about 2000 km^2 around the Wanshan Archipelago. The data obtained in the survey has the highest spatial resolution by far, which could reveal more detailed distributions and characteristics of the geologic hazards than before. In the study region, three paleo-channels that were buried about 10–30 m below the seabed were found; more than 10 shallow gas areas were discovered. The sand waves found in the region were generally small and located near the islands, and twenty pockmarks found on the seabed were mostly concentrated to north of Zhuzhou island. There are also many man-made obstacles in the region, such as wreckages, pipeline, etc. In this paper we provide a detailed distribution map of the submarine geologic hazards in this region for the first time, and discuss their formation and harmfulness, which will provide a scientific basis for marine engineering construction, marine geologic disaster prevention and mitigation.

The paleoclimate environment and recent sea level change on the seashores of Thailand Gulf in Southeast Asia

This paper analyzed and researched on several significant natural geological sections from the views of stratum-sequence stratigraphy,climate stratigraphy,event stratigraphy and regional stratigraphy by the investigation of Thailand,Malaysia and Singapore. In combination with the coupling relationship between the life-temperature of regional life zone and the evolution of geological environment,this paper exactly made out the geological sediment records of paleoclimate times in different time scales of 3 kaBP,1 kaBP and 0.5 kaBP since the past glacier age of Quaternary period,and it is consecutive and authentic for the material medium and time joint. These studies definitely reflected that the sea level of Thailand Gulf area is in tendency of continually dropping in recent years. They also provided important and new information for the global change analysis.