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1.
莱州湾瀰河三角洲滨海盐渍土,为近代松散沉积物。因海水入侵和蒸发浓缩作用,导致盐渍土(多属氯盐渍土)。根据土的物理力学性质指标,天然湿度下载荷试验和浸水载荷试验,认为:盐渍土是具有中等压缩性和湿陷性的土。盐渍土受水浸润后,土的压缩模量Es,承载力[R]明显下降,一般为浸水前的0.6倍。滨海盐渍土地区,地下水中硫酸根离子含量常大于3000毫克/升,具强结晶侵蚀性,应采取特殊防腐措施。 相似文献
2.
城华斜坡带油田位于陕甘宁盆地南端 ,延安组是一套在延长组古侵蚀面上形成的网状～曲流河沉积 ,该区的主要油组是延 8～延 10。着重讨论了城华地区延安组延 8～延 10储层渗透率非均质程度、引起强非均质性的主要原因、渗透率非均质性与沉积微相的关系以及非均质性和注采的关系。 相似文献
3.
《地球科学与环境学报》2020,(4)
前人对高山峡谷地貌区高位斜坡动响应研究较多,但对低山、丘陵地貌区斜坡强震动响应研究很少。并且,研究这类地区顺倾斜坡的地震动响应对揭示长宁M_s 6.0级地震丰富的次生山地灾害动力机理具有一定意义。在四川省长宁县丘陵地貌区典型顺倾斜坡不同部位安置强震监测仪器,捕捉到40多次余震,通过SeismoSignal软件处理典型余震数据,分析峰值加速度、阿里亚斯强度、傅里叶频谱、加速度反应谱,进而采用水平/竖直向谱比法分析局部场地效应,最后对比分析低山、丘陵地貌区与高山峡谷地貌区的斜坡动响应。结果表明:坡顶峰值加速度可达4.171 m·s~(-2),最大位移可达0.008 05 m,当峰值加速度大于1.0 m·s~(-2)时,阿里亚斯强度出现陡增的趋势;局部地形的放大效应使得地质灾害以沿山脊的裂缝及小型崩塌为主,在低频2～5 Hz处,斜坡中上部易发生山体共振。以上研究揭示了砂、页岩顺倾斜坡高位放大效应,为地震山地灾害易发性区划提供地震监测资料。 相似文献
4.
综合利用地震、钻井、油藏及地球化学资料，对珠江口盆地惠西南地区转换斜坡特征及其对油气的垂向输导作用开展了研究。研究揭示研究区发育了开放型、连接型和破坏型3类转换斜坡，已探明的油藏主要分布在转换斜坡附近或与其相连构造脊的圈闭内。3类转换斜坡对油气的垂向输导能力存在差异，破坏型转换斜坡的垂向输导性最强，与其相关的中浅层油藏储量大、充满度高；开放型转换斜坡的垂向输导性最弱，与其相关的中浅层油藏几乎不发育；连接型转换斜坡的垂向输导性则介于前两者之间。转换斜坡内微裂隙发育程度的差异决定了其垂向输导油气能力的强弱，利用位移-距离法分析认为形成破坏型转换斜坡的应力最强，微裂隙最发育，导致其垂向输导能力最强。转换斜坡输导油气差异性的认识可为珠江口盆地的油气勘探提供指导。 相似文献
5.
6.
郭翠梅 《地球科学与环境学报》1993,(4)
8号金矿脉(Q8)是小秦岭金矿田中含金量较高、具中等规模的一条金矿脉,产于小秦岭复背斜的南翼,赋存于太华群中基性火山-沉积建造的变质岩系中。矿床属中低温中深岩浆热液型矿床。矿脉长4430m,地表厚0.7～1.2m,地下最大厚度可达7m。 金赋存于金属硫化物中,尤其与黄铁矿密切相关;矿石具粒状、压碎、交代、次生四大结构类型,以粒状结构为主;矿石构造以条带状为主,其次是块状、团块状、浸染状、细脉状、晶洞状、次生构造较少;矿石类型主要是黄铁矿型和多金属硫化物型两种,金品位较高且分布广。 相似文献
7.
《地球科学与环境学报》2015,(4)
2014年8月3日16时30分,云南省昭通市鲁甸县发生Ms6.5级地震,地震诱发大量崩塌、滑坡、不稳定斜坡等次生山地灾害。结合现场调查,通过遥感图像共解译次生山地灾害点235处,灾害面积约8.59km2。基于GIS空间分析方法,利用次生山地灾害面积百分比及中心点密度2个参数,研究次生山地灾害分布规律与地震的关系;同时选取高程、坡度、坡向、岩性、距河流距离等因子统计分析了地形、岩层及河流对次生山地灾害空间分布的影响。研究区次生山地灾害面积百分比约为0.79%,中心点密度约为0.2个·km-2。结果表明:次生山地灾害点的排列受NE向昭通—鲁甸主断裂控制,63.83%的次生山地灾害发生在发震断裂带2~8km范围内,距震中越远,次生山地灾害发育率越低;次生山地灾害集中分布在1 000~1 200m高程之间和35°~45°坡度范围内,而20°~30°坡度范围内次生山地灾害中心点密度和面积百分比最大;碳酸盐岩等硬岩地层上次生山地灾害最为发育,而软岩地层中多引发高陡坡次生山地灾害;次生山地灾害整体上沿牛栏江呈线状分布,随着距河流距离的增加,其发生概率逐渐减小。 相似文献
8.
利用50余口井的储层实验资料,对苏北盆地主力勘探地区海安凹陷和高邮凹陷泰州组砂岩储层进行孔隙类型和有利储层评价。综合研究表明:海安凹陷和高邮凹陷泰州组发育三角洲、浊积扇、扇三角洲等成因类型砂体,这些砂体由成分和结构成熟度较低的长石岩屑砂岩和岩屑长石砂岩组成,并且砂岩储层发育次生孔隙,原生孔隙较少;海安凹陷泰州组储层第一个次生孔隙发育段为2 300～2 500m,系大量碳酸盐胶结物、长石和岩屑颗粒遭受强烈溶蚀而成,孔隙度为12%～25%,第二个次生孔隙发育段为2 600～3 200m;高邮凹陷泰州组储层孔隙演化与海安凹陷有一定差异,其只存在1个次生孔隙发育段(2 400～2 900m),孔隙发育程度与海安凹陷的第一个次生孔隙带相似;泰州组砂岩储层中次生孔隙的形成主要与沉积物中有机质演化产生的有机酸、酚以及碳酸有关;大部分次生孔隙是由粒间碳酸盐胶结物溶蚀产生;海安凹陷有利储层主要分布在西北部和东部三角洲前缘砂体和滑塌浊积扇砂体中,高邮凹陷有利储层主要分布在南部扇三角洲前缘砂体中,储层埋藏浅、物性好,均以Ⅰ和Ⅱ类储层为主,是有利的勘探地区。 相似文献
9.
塔里木盆地作为典型的多旋回叠合盆地,中生代以来经历了印支、燕山和喜山等多期构造运动,造成中-新生界构造格
局与古生界构造格局差异较大。应用航磁、重力、钻井、测井以及地震等资料,获得了盆地中-新生界地层分布、区域构造变形特
点和含油气性特征,兼顾基底形态和后期改造作用影响,对塔里木盆地中-新生界构造单元划分为“三坳一隆一斜坡”,即北部坳
陷区、西南坳陷区、东南坳陷区、中央隆起区和东北斜坡区5个一级构造单元和11个二级构造单元。显然,该构造单元的划分对
盆地中-新生界次生油气藏和隐蔽油气藏勘探具有重要意义。 相似文献
局与古生界构造格局差异较大。应用航磁、重力、钻井、测井以及地震等资料,获得了盆地中-新生界地层分布、区域构造变形特
点和含油气性特征,兼顾基底形态和后期改造作用影响,对塔里木盆地中-新生界构造单元划分为“三坳一隆一斜坡”,即北部坳
陷区、西南坳陷区、东南坳陷区、中央隆起区和东北斜坡区5个一级构造单元和11个二级构造单元。显然,该构造单元的划分对
盆地中-新生界次生油气藏和隐蔽油气藏勘探具有重要意义。 相似文献
10.
通过自主研发的成岩物理模拟系统,对准噶尔盆地南缘斜坡带侏罗系细砂岩进行了成岩物理模拟实验,对前陆盆地特有的埋藏方式,即沉积早期长期浅埋,沉积晚期快速深埋影响下的储层物性特征、孔隙演化规律等进行了研究。结果表明,随着模拟温度、压力和模拟埋深的逐渐增大以及压实作用的不断加强,细砂岩颗粒间接触关系由点-线-凹凸接触,粒内裂纹逐渐出现,裂纹呈不规则分布或呈共轭剪切关系;模拟埋深2 000~3 000 m时次生孔隙较为发育,孔径和喉径也表现出快速增大的趋势,埋深大于4 000 m后,次生孔隙与孔径、喉径均开始呈现递减趋势。因此,推测埋深2 000~3 000 m是准南斜坡带侏罗系有利储层发育的关键层位。 相似文献
11.
L波段对不同盐类土壤的微波介电特性分析 总被引：1，自引：0，他引：1
土壤盐碱化是世界面临的一大难题。微波遥感探测土壤具有优势,L波段对土壤含水量和含盐量较为敏感。为了分析不同盐类对土壤介电特性的影响,本文利用L波段(1.43 GHz)微波谐振腔测量了我国盐碱土中普遍存在的3种盐类(NaCl,Na2SO4,NaHCO3)土壤样品的介电常数,研究了土壤介电常数与含水量、含盐量和盐种类的关系。得出结论:实部主要由土壤的含水量决定,含盐量对实部的影响无明显规律;虚部值随含水量和含盐量的增加而增大;3种盐类土壤介电常数虚部随含盐量变化呈现不同的递增趋势,在含盐浓度一定的条件下,虚部值是ε″ NaCI>ε″ NaHCO3>ε″ Na2SO4;在某一含盐量点3种盐类土壤虚部随含水量变化的斜率不同,以此能将3种盐类区分。该研究为建立含不同盐类土壤介电常数模型和微波遥感监测土壤盐碱化提供了实验的依据。 相似文献
12.
Influences of soil moisture and salt content on loess shear strength in the Xining Basin,northeastern Qinghai-Tibet Plateau 总被引：1，自引：0，他引：1
FU Jiang-tao HU Xia-song LI Xi-lai YU Dong-mei LIU Ya-bin YANG You-Qing QI Zhao-xin LI Shu-xia 《山地科学学报》2019,(5)
Moisture and salt content of soil are the two predominant factors influencing its shear strength. This study aims to investigate the effects of these two factors on shear strength behavior of loess in the Xining Basin of Northeast Qinghai-Tibet Plateau, where such geological hazards as soil erosion, landslides collapse and debris flows are widespread due to the highly erodible loess. Salinized loess soil collected from the test site was desalinized through salt-leaching in the laboratory. The desalinized and oven-dried loess samples were also artificially moisturized and salinized in order to examine how soil salinity affects its shear strength at different moisture levels. Soil samples prepared in different ways(moisturizing, salt-leaching, and salinized) were measured to determine soil cohesion and internal friction angle. The results show that salt-leaching up to 18 rounds almost completely removed the salt content and considerably changed the physical components of loess, but the soil type remained unchanged. As salt content increases from 0.00% to 12.00%, both the cohesion and internal friction angle exhibit an initial decrease and then increase with salt content. As moisture content is 12.00%, the salt content threshold value for both cohesion and internal friction angle is identified as 3.00%. As the moisture content rises to 16.0% and 20.00%, the salt content threshold value for cohesion is still 6.00%, but 3.00% for internal friction angle. At these thresholds soil shear strength is the lowest, below which it is inversely related to soil salinity. Beyond the thresholds, however, the relationship is positive. Dissimilar to salinity, soil moisture content exerts an adverse effect on shear strength of loess. The findings of this study can provide a valuable guidance on stabilizing the engineering properties of salinized loess to prevent slope failures during heavy rainfall events. 相似文献
13.
In this paper,the process of wind erosion on two kinds of soil from the agro-pastoral area of Inner Mongolia are studied using wind tunnel experiments,considering the wind speed,blown angle of wind and soil moisture content.The results showed that the modulus of soil wind erosion increases with an increase of wind speed.When the wind speed exceeds a critical value,the soil wind erosion suddenly increases.The critical speed for both kinds of soil is within the range of 7-8m·s-1.For a constant wind speed,the rate of soil wind erosion changes from increasing to falling at a critical soil slope.The critical slope of loam soil and sandy loam soil is 20° and 10°,respectively.Soil moisture content has a significant effect on wind erosion.Soil wind erosion of both soils decreases with an increase of the soil water content in two treatments,however,for treatment two,the increasing trends of wind erosion for two soils with the falling of soil water content are no significant,especially for the loam soil,and in the same soil water content,the wind erosion of two soils in treatment one is significantly higher than treatment two,this indicates reducing the disturbance of soil surface can evidently control the soil wind erosion. 相似文献
14.
The Tangba high slope is mainly composed of coarse soils and supplies core wall materials for the construction of the Changheba dam. Since the filling intensity of the Changheba dam is high, the Tangba high slope suffers from a high-intensity excavation process, and reinforcement measures are usually not implemented immediately. Moreover, the distribution of useful materials is uneven and insufficient, and the mixing of different soil materials is necessary; thus, multiple simultaneous excavations and secondary excavation are inevitable. In the construction period from 2012 to 2016, large deformations occurred in this area, and one of the largest monitored horizontal deformations whose direction points to the opposite side of the valley even reached more than 8000 mm. According to field investigation, site monitoring and theoretical analysis, the large deformation in the Tangba high slope can be divided into two phases. In the first phase, the excavation construction breaks the original stress equilibrium state; in the second phase, the precipitation infiltration accelerates the deformation. Thus, the excavation construction and precipitation infiltration are the two major factors promoting the deformation, and the high-intensity and complex excavation process is the fundamental cause. Notably, rate of slope deformation significantly accelerated in rainy seasons due to precipitation infiltration; the rate also accelerated in early 2016 due to the high-intensity, complex excavation process. Comprehensively considering the above factors, timely and effective reinforcement measures are essential. 相似文献
15.
资江是洞庭湖的第二大支流，其中上游锑(Sb)矿采矿冶炼工业发达，给资江下游及洞庭湖区带来了严重的重金属污染风险。以资江河口区为研究区，采集了132个农田土壤样品及7个资江水样，综合采用多种污染评价方法、空间分析、多元统计分析方法对研究区重金属进行了污染评价及来源分析。结果表明，研究区农田土壤重金属平均质量分数表现为Zn>Cr>Ni>Pb>Cu>As>Sb>Cd，旱田土壤重金属平均质量分数除Pb外均高于水田。Sb、As、Cd为主要污染元素，Sb达到了中等污染和中等生态风险的程度，总体处于轻微-中等生态风险程度。资江水体Sb质量浓度较高，平均为10.51 μg/L。Sb主要来源于中上游的锑矿工业，受高锑质量浓度地表水灌溉、垃圾填埋场以及燃煤等人为活动的控制；Cd主要来源于农药化肥、生活垃圾和城镇废水等人为活动；Cr主要来源于成土母质，而Cu、Zn、As、Ni、Pb受成土母质和人为活动的双重控制。 相似文献
16.
泥质砂岩残积土作为一种结构性很强的特殊土, 具有崩解性强、抗冲蚀性差以及扰动性极大的特点, 对工程建设有较大影响。为了探究泥质砂岩残积土边坡降雨冲刷机理, 设计了边坡降雨冲刷试验, 通过现场三维激光扫描技术测试分析了其表面冲刷效应; 利用高密度电法进一步明确了泥质砂岩残积土边坡的入渗特性、表面冲刷演化机制及冲刷破坏机理。结果表明: 冲刷试验的最初阶段, 降水入渗强且主要向坡脚处运移, 坡表未形成明显的细沟; 冲刷试验中期, 坡脚处土体最先达到饱和而形成坡面径流, 细沟贯通扩大形成小规模冲槽以及片蚀区; 冲刷试验后期, 坡面中部和坡脚处土体冲蚀严重, 坡脚处的冲槽向上部延伸, 片蚀区扩大, 导致表层土体结构发生变化, 渗透性差异明显; 泥质砂岩残积土坡体降雨冲刷主要划分为表层溅蚀、下层潜蚀和细沟贯通3个阶段, 坡面土体流失主要发生在最后一个阶段, 细沟率达到最高值16.9%, 细沟贯通率也高达0.74。研究结果可以为深入探讨泥质砂岩残积土边坡冲蚀防护和研究冲蚀防护机理提供基础资料。 相似文献
17.
SPATIAL-TEMPORAL VARIATION OF HEAVY METAL ELEMENTS CONTENT IN COVERING SOIL OF RECLAMATION AREA IN FUSHUN COAL MINE 总被引：3，自引：2，他引：1
Grid method is employed for sampling covering soil at the test field, which is reclamation area filled bycoal mining wastes for cropland in the Fushun coal mine, Liaoning Province, the Northeast China. The soil samples aretaken at different locations, including three kinds of covering soil, three different depths of soil layers and four differentcovering ages of covering soil. The spatial-temporal variation of heavy metal element content in reclamation soil is studied. The results indicate that the content of heavy metal elements is decreasing year after year; the determinant reasonwhy the content of heavy metal elements at 60cm depth layer is higher than that at 30em depth layer and surface is fertilizer and manure apphcation; the metal elements mainly come from external environment; there is no metal pollution comingfrom mother material (coal mining wastes) in plough layer of covering soil. 相似文献
18.
Based on data from 22 sample plots and applying the Canonical Correspondence Analysis (CCA),this paper discusses the vegetation-environment relationships between the northern slope of Karlik Mountain and Naomaohu Basin,which is situated in the easternmost end of the Tianshan Mountains,Xinjiang Uygur Autonomous Region,China.For the zonal vegetation,community diversity of mountain vegetation is higher than that of the desert vegetation due to environmental factors.The CCA ordination diagram revealed that the composition and distribution of vegetation types are mainly determined by altitude,soil pH and soil salt content.With increasing elevation,the soil pH and total salt content decrease but the contents of soil organic matter,soil water,total nitrogen and total phosphorus increase gradually.In the CCA ordination diagrams,the sample plots and main species can be divided into five types according to their adaptations to the environmental factors.Type I is composed of desert vegetation distributed on the low mountains,hills,plains and deserts below an elevation of 1900 m;type II is distributed in the mountain and desert ecotone with an elevation of 1900-2300 m,and includes steppe desert,desert steppe and wetland meadow;type III is very simply composed of only salinized meadow;type IV is distributed above an elevation of 2300 m,containing mountain steppe,meadow steppe,subalpine meadow and alpine meadow;type V only contains salinized meadow.The results show that with increasing elevation,species combination changes from the xerophytic shrubs,semi-shrubs and herbs distributed in the low altitude zone with arid climate to the cold-tolerant perennial herbs growing in the high altitudinal zone with cold climate. 相似文献
19.
通过测定雷州半岛南部845个耕地土壤样品pH、有机质、全氮、有效磷、速效钾、碱解氮的含量,采用层次分析法确定各肥力评价指标权重,应用模糊数学法对该区域耕地土壤肥力进行综合评价,并利用ArcGIS 9.2软件对土壤肥力空间变异进行分析.结果表明:雷州半岛南部土壤有机质、全氮、有效磷、速效钾、碱解氮平均值分别为26.18 g/kg、1.48 g/kg 、34.63 mg/kg、158.57 mg/kg、133.17 mg/kg;土壤速效磷的变异系数最高,为103.14%,属强变异性,有机质、速效钾、碱解氮、全氮的变异系数属中等变异性,pH值的变异系数最小.土壤肥力总体水平处于中等偏低;从空间分布来看,土壤肥力中部高,东北、西南部相对较低 相似文献
20.
Quantification of 3D macropore networks in forest soils in Touzhai valley (Yunnan,China) using X-ray computed tomography and image analysis 总被引：1，自引：0，他引：1
The three dimensional(3D) geometry of soil macropores largely controls preferential flow, which is a significant infiltrating mechanism for rainfall in forest soils and affects slope stability. However, detailed studies on the 3D geometry of macropore networks in forest soils are rare. The intense rainfall-triggered potentially unstable slopes were threatening the villages at the downstream of Touzhai valley(Yunnan, China). We visualized and quantified the 3D macropore networks in undisturbed soil columns(Histosols) taken from a forest hillslope in Touzhai valley, and compared them with those in agricultural soils(corn and soybean in USA; barley, fodder beet and red fescue in Denmark) and grassland soils in USA. We took two large undisturbed soil columns(250 mm×250 mm×500 mm), and scanned the soil columns at in-situ soil water content conditions using X-ray computed tomography at a voxel resolution of 0.945 × 0.945 × 1.500 mm~3. After reconstruction and visualization, we quantified the characteristics of macropore networks. In the studiedforest soils, the main types of macropores were root channels, inter-aggregate voids, macropores without knowing origin, root-soil interface and stone-soil interface. While macropore networks tend to be more complex, larger, deeper and longer. The forest soils have high macroporosity, total macropore wall area density, node density, and large macropore volume, hydraulic radius, mean macropore length, angle, and low tortuosity. The findings suggest that macropore networks in the forest soils have high interconnectivity, vertical continuity, linearity and less vertically oriented. 相似文献