郯庐断裂带新沂—泗洪段土壤气Rn体积活度和CO2浓度特征研究     

缪阿丽  张扬  方震  李锋  王维  高力 《地震》2019,39(1):48-57

郯庐断裂带江苏段地区4个剖面进行了土壤气Rn体积活度和CO₂浓度测量结果显示, 自北向南土壤气Rn体积活度均值分别为22.9 kBq/m³、 35.5 kBq/m³、 40.2 kBq/m³、 26.6 kBq/m³; 自北向南土壤气CO₂浓度均值分别为0.669%、 0.400%、 0.503%、 1.109%。 土壤气Rn体积活度和CO₂的浓度在空间分布上具有较好的一致性, 这可能与CO₂是Rn的载气有关。 综合分析土壤气Rn和CO₂测量结果以及水准资料可得, 2017年土壤气Rn高值出现在晓店段可能与区域应力应变调整有关。 本研究不仅为研究区以后的土壤气研究提供了参考, 同时也可为研究区的构造活动研究提供地球化学资料参考。  相似文献   

汤东活动断裂带土壤H2、Rn地球化学特征     

胡宁  马志敏  王明亮  王宇  娄露玲  夏修军  张宝山  王文净  郭德科 《地震》2019,39(2):174-182

为研究汤东断裂带土壤气体地球化学特征及其所反映的构造地球化学背景, 采用野外监测的方法分析了张河村与邢李庄村两条测线的土壤H₂、 Rn分布特征。 结果表明, 张河村H₂浓度、 Rn活度浓度的分布范围分别为0.24×10^-6～174.7×10^-6、 13.3～69.8 kBq·m^-3, 背景值分别为14.26×10^-6, 24.8 kBq·m^-3。 邢李庄测线H₂浓度、 Rn活度浓度的分布范围11.8×10^-6～67.06×10^-6、 43.6～72.6 kBq·m^-3, 背景值分别为37.13×10^-6、 72.6 kBq·m^-3。 张河村测线在90～105 m处, H₂、 Rn出现强烈高值异常, 而120～150 m处出现高值异常。 异常值位于断裂带附近, H₂、 Rn气体测值对断裂位置具有良好的指示作用。 气体异常主要受汤东活动断裂构造控制, 汤东断裂下方的深大断裂和汤阴地堑中下地壳的低速体对深部气体释放有重要作用。  相似文献   

Partition-coordinated control of soil and water loss for chestnut forests in the Yanshan Mountain Region,China   总被引：1，自引：0，他引：1  

Xinhui Ding  Guangquan Liu  Xiaoying Liu  Yongsheng Xie  Zhichun Yue 《国际泥沙研究》2019,34(1):58-64

Soil erosion from chestnut forests is one of the most important factors causing land degradation in the Yanshan Mountain Region. A 2-year field study was done to compare the effects on erosion of a control plot (CP), a repaired and maintained horizontal ditch built with an engineering baffle every 6?m (MP 1), and a repaired and maintained horizontal ditch built with an engineering baffle every 8?m (MP 2). The results showed that the slope runoff of chestnut forests was influenced by rainfall characteristic factors. No single rainfall characteristic factor showed dominance for hill slope runoff. The runoff reduction effect of the partition-coordinated erosion control measures (MP 1 and MP 2) was substantial for chestnut forests under high rainfall intensity conditions. However, the runoff reduction efficiency was higher under the conditions of heavy rainfall and low average rainfall intensity than for storms with higher intensity and lower total rainfall. The reduction effect of the partition-coordinated erosion control measures on the runoff and sediment yield of chestnut forest slopes was MP 2 > MP 1 > CP. The runoff reduction rate and erosion reduction rate of MP 2 reached 61.70% and 97.41%, respectively, and that for MP 1 was 54.15% and 85.31%, respectively. Therefore, after a comprehensive comparison, MP 2 was determined to be more effective for soil erosion control for a sloping chestnut forest.  相似文献   

Effects of rainfall patterns on runoff and rainfall-induced erosion   总被引：3，自引：0，他引：3  

Morteza Alavinia  Farzin Nasiri Saleh  Hossain Asadi 《国际泥沙研究》2019,34(3):270-278

Rainfall-induced erosion involves the detachment of soil particles by raindrop impact and their transport by the combined action of the shallow surface runoff and raindrop impact. Although temporal variation in rainfall intensity (pattern) during natural rainstorms is a common phenomenon, the available information is inadequate to understand its effects on runoff and rainfall-induced erosion processes. To address this issue, four simulated rainfall patterns (constant, increasing, decreasing, and increasing - decreasing) with the same total kinetic energy were designed. Two soil types (sandy and sandy loam) were subjected to simulated rainfall using 15?cm × 30?cm long detachment trays under infiltration conditions. For each simulation, runoff and sediment concentration were sampled at regular intervals. No obvious difference was observed in runoff across the two soil types, but there were significant differences in soil losses among the different rainfall patterns and stages. For varying-intensity rainfall patterns, the dominant sediment transport mechanism was not only influenced by raindrop detachment but also was affected by raindrop-induced shallow flow transport. Moreover, the efficiency of equations that predict the interrill erosion rate increased when the integrated raindrop impact and surface runoff rate were applied. Although the processes of interrill erosion are complex, the findings in this study may provide useful insight for developing models that predict the effects of rainfall pattern on runoff and erosion.  相似文献   

Anaerobic Biodegradation of Ethylic and Methylic Biodiesel and Their Impact on Benzene Degradation     

《洁净——土壤、空气、水》2017,45(6)

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基于新型单相MICP技术改性黏性土力学特性的试验研究     

张宽  唐朝生  刘博  张天生  程青  施斌 《工程地质学报》2020,28(2):306-316

微生物诱导碳酸钙沉积(MICP)是一种绿色低碳的新型土体改性技术.该技术当前主要适用于渗透性较好的砂土,普遍使用两相处理方法,即菌液和胶结液分开施用.然而,对于渗透性相对较差的黏性土,传统的两相处理方法难以适用.为此,引入新的单相胶结方法,即菌液和胶结液混合施用,通过调节溶液的初始pH值为细菌水解作用提供窗口期,避免微生物絮凝阻塞孔隙,使混合液均匀分布于土体一定深度范围内,从而达到显著提升胶结效果的目的.利用喷洒法将混合液喷洒至土体表层进行MICP处理,处理完成后使用超微型贯入仪SMP-1测试土体表层不同深度处的结构强度,分析土体力学特性的空间差异,对土体的胶结效果进行定量评价.此外,探究了胶结液浓度(0.2M、0.5M和1.0M)及胶结方法(调节pH与否)对于土体结构强度及MICP改性效果的影响.结果表明:采用单相MICP技术对黏性土进行改性,能够显著提高其结构强度,具有较好的适用性;在不高于1.0 M的胶结液浓度范围内,黏性土的胶结效果随着胶结液浓度增加而提升;相比较而言,调节pH的单相胶结方法对于提升土体胶结的深度和均匀性有明显积极作用.新型单相MICP技术简单易行,能够节约成本,在黏性土表层加固方面具有潜在推广应用价值.  相似文献   

基于最大球算法定量表征土体空间孔隙网络     

解朝阳  张巍  姚东方  王坚  朱雨辰 《工程地质学报》2020,28(1):60-68

孔隙网络控制着土体渗流、排水固结与基质吸力等重要工程性质。本文介绍了多孔介质孔隙网络最大球建模基本原理与算法。以显微CT扫描振捣干法生成的南京粉砂试样为例,采用最大球算法建立了试样三维重构模型表征单元体(REV)的空间孔隙网络球棍模型,计算得到了样品REV尺度的孔隙网络参数,统计发现,孔隙半径、喉道半径、孔隙配位数、孔隙截面形状因子、喉道截面形状因子与喉道长度等孔隙参数均近似服从正态分布,孔隙体积近似服从衰减型指数分布。孔隙与喉道半径分别分布在100μm与65μm以内,两者数学期望分别为40. 0μm与18. 0μm;配位数分布在25以内,数学期望为5. 1;孔隙与喉道截面形状因子分别分布在0. 01~0. 04与0. 01~0. 05的区间内,两者数学期望分别为0. 019与0. 033;喉道长度分布在100~800μm以内,数学期望为292. 22μm。同时发现,样品中体积小于1. 5×10^7μm^3的小孔隙数量超过90%。本方法可应用于土体细观孔隙结构的定量表征。  相似文献   

Probabilistic analysis of soil‐structure interaction effects on the seismic performance of structures          下载免费PDF全文

Fariborz Mirzaie  Mojtaba Mahsuli  Mohammad Ali Ghannad 《地震工程与结构动力学》2017,46(4):641-660

This paper revisits the phenomenon of dynamic soil‐structure interaction (SSI) with a probabilistic approach. For this purpose, a twofold objective is pursued. First, the effect of SSI on inelastic response of the structure is studied considering the prevailing uncertainties. Second, the consequence of practicing SSI provisions of the current seismic design codes on the structural performance is investigated in a probabilistic framework. The soil‐structure system is modeled by the sub‐structure method. The uncertainty in the properties of the soil and the structure is described by random variables that are input to this model. Monte Carlo sampling analysis is employed to compute the probability distribution of the ductility demand of the structure, which is selected as the metrics for the structural performance. In each sample, a randomly generated soil‐structure system is subjected to a randomly selected and scaled ground motion. To comprehensively model the uncertainty in the ground motion, a suite of 3269 records is employed. An extensive parametric study is conducted to cover a wide range of soil‐structure systems. The results reveal the probability that SSI increases the ductility demand of structures designed based on the conventional fixed‐based assumption but built on flexible soil in reality. The results also show it is highly probable that practicing SSI provisions of modern seismic codes increase the ductility demand of the structure. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Isolation and Identification of Two Novel Alkaligenous Arsenic(III)‐Oxidizing Bacteria From a Realgar Mine,China     

《洁净——土壤、空气、水》2017,45(1)

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Response of fish communities in rivers subjected to a high sediment load     

《Limnologica》2017

Erosion and sediment yield are a significant problem in the Guadalquivir River basin. Such phenomena are largely driven by a land use devoted to intensive cultivation of olive trees, with a large socioeconomic influence in Andalusia. This sediment overload in rivers causes serious impacts on all fluvial ecosystem components.In this study we assess the chronic effect of sediment yield on fish communities at 104 river sites located in two different sub-catchments – the Bembézar and Guadajoz rivers – both with different lithological composition and erosion rates. Sediment yield was estimated using a semi-quantitative Factorial Score Model (FSM), developed specifically for Spanish rivers. The fish populations of both basins were evaluated in composition and abundances by the study of Fernández-Delgado et al., 2014. The influence of sediment yield on the fish community was analyzed using General Additive Models.The sediment yield was higher in the Guadajoz basin (921 T/Km2 per year) than in Bembézar (701 T/Km2 per year). In the former, fish communities were poorer in both fish density and diversity, with Luciobarbus sclateri as the only substantially present species and a significant relationship between sediment yield and load, and fish density. In contrast, in the Bembézar basin, sediment yield was correlated with total fish density, including Luciobarbus sclateri, Pseudochondrostoma willkommii, Cobitis paludica, Iberochondrostoma lemmingii, Anaecypris hispanica, and Cyprinus carpio. Intermediate values of sediment yield led to maximum densities, while those higher decreased the density of these species.  相似文献