多工况下汉源二蛮山滑坡机理数值模拟     

陶骞  刘超  朱志铭  杨勇  邹祖银 《地质力学学报》2012,18(4):440-450

利用FLAC3D软件对四川省雅安市汉源县二蛮山滑坡坡体进行建模,模拟降雨滑坡过程,并进行应力应变特征及稳定性计算分析,从而为深入研究地震及降雨诱发再次滑坡及防灾减灾提供可靠依据。研究中假设地震工况,对边坡进行详细的动力分析,得到了各监测点动力特征曲线;通过降雨工况下坡体稳定性系数分析得到了不同强度折减安全系数。研究结果表明,滑源区相对特殊的地形条件和地质构造以及不利的结构面组合是滑坡的基础;前期强降雨期间饱水加载以及大量雨水沿斜沟张裂结构面的下渗软化作用,是诱发滑坡发生的关键因素。   相似文献   

非均质包气带三氮累积转化模拟砂箱试验          下载免费PDF全文

刘超  何江涛  沈杨  刘玉梅  陈鸿汉 《地学前缘》2012,19(6):236-242

为研究包气带非均质结构对氮素迁移转化的影响,采用室内砂箱实验模拟了1.72 mm/h降雨强度下NH₄-N污染非均质包气带的过程。通过观测出水及土壤溶液中NH₄-N、NO₂-N和NO₃-N质量浓度变化,分析探讨了NH₄-N在含有两个亚粘土透镜体的非均质包气带介质中的迁移转化和累积时空分布特征。结果表明：经过89 d物理吸附和微生物作用,出水NH₄-N首先迅速增加然后逐渐减小,而出水NO₃-N含量持续增加,其间NO₂-N出现累积峰,系统最终达到平衡稳定状态;土壤溶液中NH₄-N在两亚粘土透镜体上表面累积较多,NO₃-N和NO₂-N在上透镜体中的累积含量大于下透镜体;而砂槽上部土壤中出现明显的NO₃-N累积,NH₄-N和NO₂-N则在下部土壤和亚粘土透镜体中累积较多。包气带介质质地、粗 细交互结构及降雨淋溶、水分运移对“三氮”的迁移转化和富集有重要影响。  相似文献   

合山市矿山地质环境影响评价研究   总被引：3，自引：1，他引：2  

唐朝晖  刘楠  柴波  周建伟 《水文地质工程地质》2012,39(6):124-10

广西合山属于煤炭资源枯竭型城市,正在经历的市域经济转型与大规模城市建设,使得矿山地质环境影响评价成为一项基础性工作。将矿山地质环境影响评价划分为两个层次,即采矿活动对矿山地质环境影响评价和城市建设对地质环境的影响评价。选取矿山地质环境条件、矿山开采状况、矿山地质环境问题3个地质环境要素,地形地貌、植被覆盖率、岩土体工程特征、矿山分布密度、煤层倾斜角度、煤层采深采厚比、土地资源破坏强度、水资源破坏强度、地质灾害发育强度9个评价指标,首先应用模糊综合评价模型进行了第一层次的矿山地质环境影响评价,然后采用综合指数评价模型进行了第二层次的地质环境影响评价,结果显示,影响严重区、较严重区、一般区分别为62.87,118.84,175.99km2,各占市域面积的17.6%、33.2%、49.2%。评价结果可作为合山市矿山地质环境综合治理的重要依据。  相似文献   

旅游活动对黄石寨景区步道的影响评估   总被引：8，自引：3，他引：5  

钟林生  柴江豪  谢婷  石强 《地理研究》2008,27(5):1071-1077

作为旅游景区基础设施的步道,高频率旅游利用会对其产生一定程度的影响。选取张家界森林公园的黄石寨景区为研究对象,运用"既成事实调查法",设置30个样点,选取了若干特征与指标来评估步道的受影响情况。结果显示,景区的步道扩展率为13.5%,步道冲蚀发生率为73.3%,步道损毁有14处,步道边缘的土壤性状和植被状况也发生了改变,这说明旅游活动对黄石寨景区步道产生了负面影响。而且山顶环寨游道受到旅游活动的影响最大,上山游道次之,下山游道最小,这与旅游利用强度密切相关。  相似文献   

沂沭断裂带构造区光弹实验与地震危险区判定研究     

黄兴  胡宏玖  王华林  黄大卫  王纪强  陈平  胡超  刘军  刘红欣 《中国地震》2015,31(3):529-543

在对沂沭断裂带的地质构造环境、断裂带分布特征进行详细分析的基础上,采用聚碳酸酯材料制成沂沭断裂带构造区域的地质模型,分别运用集中、2点和均布等加载方式,使用光弹实验方法模拟特定构造框架下应力、应变场的变化特征。通过对光弹实验数据的分析,在对比不同加载方式下应力积累区域和地震危险区的基础上判定沂沭断裂带构造区中的地震危险区域。  相似文献   

Research on meteorological thresholds of drought and flood disaster: a case study in the Huai River Basin,China   总被引：4，自引：3，他引：1  

Chao Gao  Zhengtao Zhang  Jianqing Zhai  Liu Qing  Yao Mengting 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(1):157-167

Together with affected areas of crops from 1978 to 2008, the daily precipitation of 110 stations located in the Huai River Basin during 1959–2008 was used to study the critical conditions when drought and flood occur, based on which the quantitative relationship between the critical condition and the affected area of crops was further studied. Based on the research on the hazard-formative factor of precipitation and the damage degree of crops, the spatial-temporal characteristics of disasters were analyzed, the drought and flood disaster-causing threshold was determined, and the quantitative relationship between the disaster-causing threshold and affected area of crops was established. The results are as the follows: (1) During 1959–2008, extreme precipitation levels were high in the eastern and western part of the Huai River Basin and were low in its central part; the spatial distribution of the coefficient of variation (CV) differed greatly from average extreme precipitation: the series of most stations were located in the central basin, and especially there was a positive trend in Anhui and Henan Provinces. (2) The cumulative precipitation during the disaster period of each station was divided by its mean cumulative precipitation during the same period in 1959–2008 to obtain the disaster-causing threshold, which has shown a good effect on reflecting the actual grade and affected areas in disasters. (3) The relationship among disaster grade, disaster-causing threshold and damage area of crops was established; this threshold can be used as a tool for agricultural disaster assessment and early warning, and can effectively improve the ability to prevent and mitigate disaster in the Huai River Basin. (4) The disaster-causing threshold can be an important input parameter for hazard assessment; other underlying surface indicators can be good supplements for determining the threshold in hazard assessment.  相似文献   

In situ determination of hafnium isotopes from rutile using LA-MC-ICP-MS     

Yang Li  YueHeng Yang  ShuJuan Jiao  FuYuan Wu  JinHui Yang  LieWen Xie  Chao Huang 《中国科学:地球科学(英文版)》2015,58(12):2134-2144

The hafnium isotopic analysis using laser ablation has been widely conducted on Hf-rich minerals(zircon/baddeleyite/ calzirtite/eudialyte), however, little work has been reported on Hf-poor(100 ppm) minerals. This work presents a detailed procedure of in situ hafnium isotopic analysis from rutile using laser ablation multiple collector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS). The rutile U-Pb dating reference material JDX shows homogeneous hafnium isotopic ratios, with 176Hf/177Hf=0.281795±0.000015(2SD, n=33) and 176Lu/177Hf=0.000018±0.000004(2SD, n=17) that suggest the possibility of using JDX as a new reference material hafnium isotopic measurement. We also measure hafnium isotopic compositions of other rutile U-Pb dating reference material(R10, Sugluk-4 and PCA-S207) and the 176Hf/177 Hf values are similar to previously reported results, which confirms that we can acquire accurate and precise hafnium isotopic compositions using our developed analytical protocol. We analyzed hafnium isotopic compositions and U-Pb ages of rutile in high-temperature and ultrahigh-temperature granulites from various terrains of the Khondalite Belt from the North China Craton, combined with zircon results in the same area, suggesting that the metamorphic evolution history of the granulite is much more complicated than previously thought.  相似文献   

渗流影响下岩石损伤和渐进破裂演化过程的数值试验研究   总被引：1，自引：1，他引：0       下载免费PDF全文

付金伟  朱维申  张敦福  贾超 《水文地质工程地质》2015,42(1):53-59

在FLAC-3D软件平台上,开发出岩石破裂过程的渗流-损伤耦合分析程序,对渗流-损伤耦合作用下岩石的裂纹萌生、扩展过程进行模拟研究。分析了在孔隙水压力作用下,含原生裂隙和弱化单元的非均质试件在单轴、三轴加载下的破坏过程,并与非渗流条件下试件在单轴、三轴压缩下的破坏过程相对比,通过动态显示损伤状态、渗流场,并分析应力应变关系、位移图等,对渗流影响下裂隙岩体的损伤和渐进破裂过程进行了研究。  相似文献   

内蒙古阿巴嘎旗乌和尔楚鲁图钼矿区成矿斑岩的岩石地球化学特征与年代学     

俞礽安  唐永香  张峰  谢瑜  张超  郭虎 《吉林大学学报(地球科学版)》2015,45(4):1098-1111

乌和尔楚鲁图钼矿床位于国内重要的二连东乌旗钼矿成矿带中,为近几年新发现的斑岩型钼矿床.本次就该矿床成矿岩体的地球化学及其U-Pb年代学开展相关研究.结果表明: 矿区中的成矿岩体属过铝质、高钾钙碱性系列;富集大离子亲石元素(LILE)、亏损高场强元素(HFSE),具有与南岭型花岗岩相似的地球化学特征.锆石LA-ICP-MS U-Pb定年显示,与乌和尔楚鲁图钼矿床成矿有关的花岗斑岩形成于中侏罗世((160 ± 1)Ma).因此,可推测乌和尔楚鲁图钼矿床斑岩型钼矿的成矿时代为燕山早期.综合研究认为乌和尔楚鲁图斑岩型钼矿床形成于后碰撞的构造环境.  相似文献   

基于WiFi信号室内定位技术的研究   总被引：1，自引：0，他引：1  

靳超  邱冬炜 《测绘通报》2017,(5):21-25

主要对基于WiFi信号的室内定位技术中的三角形定位法进行了研究。鉴于现有的三角形定位模型受信号强度和环境干扰的约束影响,定位精度不高,提出了一种结合室内影响因素约束的权重改正定位模型,更加切合复杂的室内定位环境。通过试验测试和数据分析,经过加权去噪模型改正后的定位精度更高,适用性更广。  相似文献