Quantitative monitoring of gravity erosion using a novel 3D surface measuring technique: validation and case study

Natural Hazards - Gravity erosion is one of the most remarkable natural hazards in mountainous regions, especially on the Loess Plateau of China. Nevertheless, the measurement of failure mass is...     

山东沂水太古宙麻粒岩区年代学研究成果简介

本文以详细研究本区麻粒岩-斜长角闪岩等表壳岩的岩石学、地球化学和 Sm-Nd 同位素定年为重点。所取得的成果，对华北陆台古老地层的分布和古构造格局的探索提供了实际资料。     

The stability of Foundation Rock in Gezhouba Project

The results of the stability study of dam foundation , including the effects of ground stresses on the stability of base masses and long-term stability and strength of weak intercalations , especially of clayey ones, are presented. It is proved that the considerable tectonic stresses exist even in red rock layers with slight folds and a gentle terrain and that the stability of masses are directly affected by local stress relief. It is found that sedimentary rock behaves like rheology. A method of deter-mining long-term strength of rheological rock is suggested.     

相山邹家山铀矿区某钻孔岩心高光谱蚀变矿物特征及地质意义

文章基于高光谱蚀变矿物提取方法,利用邹家山地区某钻孔岩心的高光谱数据进行蚀变矿物提取和编录,提取的蚀变矿物主要有富铝水云母、贫铝水云母、绿泥石、蒙脱石、碳酸盐、地开石、高岭石。其中水云母化、绿泥石化、赤铁矿化与铀矿化密切相关;富铝水云母在钻孔上部含量多而下部含量减少;贫铝水云母在钻孔上部含量少,而在下部尤其是矿化段含量明显增多,不同蚀变矿物分布形态不同且不同部位蚀变矿物组合不同,反映了矿区经历了不同期次和性质的热液活动。     

乳山金矿煌斑岩的Sm-Nd同位素研究

乳山金矿区发育多种与金矿脉在时空上密切伴生的煌斑岩脉。煌斑岩的稀土元素含量和配分曲线与胶东群残留体和昆嵛山花岗岩的均较相似；三者的εNd(t)、INd(t)和tDM亦甚为相近。胶东群的分异熔融作用，可较好地解释煌斑岩与花岗岩和胶东群残留体在成因上的渊源关系。     

Non-coaxiality of soft clay generated by principal stress rotation under high-speed train loading

Plenty of geomechanics tests and theories have confirmed the existence of non-coaxiality while soil is subjected to principal stress rotation. This paper investigated the influence of one particular principal stress path, which is a ‘heart-shape’ stress path that is normally induced by high-speed train loading, on the non-coaxiality of reconstituted soft clay. Hollow cylinder apparatus was employed to carry out series of undrained dynamic tests. The goals of this study were to (1) reveal the essential factors of complex cyclic loading paths that influence non-coaxiality in clayey soil and (2) quantify the influence of the factors on variation in non-coaxiality under the high-speed training loading. To analyze the non-coaxiality under high-speed train loading, (a) the pure rotation stress path was utilized as comparison for underling the different influence that ‘heart-shape’ stress path has from other conventional cyclic stress paths. (b) Two variables, dynamic stress ratio and tension–compression amplitude ratio, were introduced in analyzing the evolution of the non-coaxial angle. (c) Based on the test results, equations for describing the revolution of non-coaxiality were proposed which can help to describe the variation in non-coaxial angle under complex loadings quantitatively and understand the influence of the major factors of the stress path intensively.

     

奎屯河流域南洼地地下水补给特征分析

独山子石油化工基地第二水源地(简称二水源)位于新疆奎屯河流域南洼地,认识和掌握南洼地地下水补给特征是研究和评价独山子石化基地用水保障程度的重要基础。通过南洼地地下水和主要河流的水化学、环境同位素特征分析,对南洼地地下水的补给得到如下认识:二水源西北缘和中部主要接受奎屯河、小巴音沟水的补给,其东南缘主要接受乌兰布拉克沟和乔路特沟地表水的补给;就整个二水源来讲,奎屯河与小巴音沟的补给是主要的。     

东营凹陷南坡近地表化探研究

利用引进的近地表化探系统,在济阳拗陷东营凹陷南坡的草桥油田进行了化探资料的采集、分析、处理及解释。研究证明:该系统在资料采集和现场质量控制方面有着明显的技术优势,在己知油田的断层、油水边界和油层尖灭线都有明显的地化异常。通过各种方法实验,对烃类在纵向上、横向上的丰度变化进行了初步探索。     

Comprehensive analyses of the initiation and landslide-generated wave processes of the 24 June 2015 Hongyanzi landslide at the Three Gorges Reservoir,China

Reservoir landslides pose a great threat to shipping safety, human lives and properties, and the operation of the hydropower station. In this paper, the 24 June 2015 Hongyanzi landslide at the Three Gorges Reservoir is considered as an example to study the initiation mechanism and landslide-generated wave process of a reservoir landslide. The finite difference method and limit equilibrium analysis are used to analyze the deformation and failure characteristics of the Hongyanzi slope. Simulation results show that a large deformation (about 358 mm) happens in the shallow deposits under intermittent rainfall condition, and the slope is in a limit state. At the same time, continuous rapid drawdown of the water level (about ?0.55 m/day during 8–24 June 2015) reduced the support and accelerated the drainage of the water for the bank slope. A coupling effect of intermittent rainfall and rapid drawdown of the water level was the triggering factor of the 24 June Hongyanzi landslide. Landslide-generated wave process was simulated using a fluid–solid coupling method by integrating the general moving object collision model. Simulation results show that the landslide-generated wave is dominated by the impulse wave, which is generated by sliding masses entering the river with high speed. The maximum wave height is about 5.90 m, and the wave would decay gradually as it spreads because of friction and energy dissipation. To prevent reservoir landslides, the speed for the rising or drawdown of the water level should be controlled, and most importantly, rapid drawdown should be avoided.     

Rare earth elements (REE) of dissolved and suspended loads in the Xijiang River, South China

The Xijiang River is the main channel of the Zhujiang (Pearl River), the second largest river in China in terms of water discharge, and flows through one of the largest carbonate provinces in the world. The rare earth element (REE) concentrations of the dissolved load and the suspended particulate matter (SPM) load were measured in the Xijiang River system during the high-flow season. The low dissolved REE concentration in the Xijiang River is attributed to the interaction of high pH and low DOC concentration. The PAAS-normalized REE patterns for the dissolved load show some common features: negative Ce anomaly, progressively heavy REE (HREE) enrichment relative to light REE (LREE). Similar to the world’s major rivers the absolute concentration of the dissolved REE in the Xijiang River are mainly pH controlled. The degree of REE partitioning between the dissolved load and SPM load is also strongly pH dependent. The negative Ce anomaly is progressively developed with increasing pH, being consistent with the oxidation of Ce (III) to Ce (IV) in the alkaline river waters, and the lack of Ce anomalies in several DOC-rich waters is presumably due to both Ce (III) and Ce (IV) being strongly bound by organic matter. The PAAS-normalized REE patterns for the dissolved load and the SPM load in rivers draining the carbonate rock area exhibit middle REE (MREE) enrichment and a distinct maximum at Eu, indicating the preferential dissolution of phosphatic minerals during weathering of host lithologies. Compared to the Xijiang River waters, the MREE enrichment with a maximum at Eu disappeared and light REE were more depleted in the South China Sea (SCS) waters, suggesting that the REE sourced from the Xijiang River must be further fractionated and modified on entering the SCS. The river fluxes of individual dissolved REE introduced by the Xijiang River into the SCS vary from 0.04 to 4.36 × 10⁴ mol a⁻¹.