岩溶峰丛洼地不同环境水土流失差异及防治研究——以广西果化岩溶生态研究基地为例

与碎屑岩地区相比,特殊的岩溶水文地质结构,导致岩溶区存在不同的水土流失过程和特点,尤以峰丛洼地区最具代表性。通过广西平果县果化岩溶峰丛洼地土壤地表侵蚀和地下漏失的调查研究显示:洼地不同地貌部位水土流失差异较大,从山峰、垭口、山坡、山麓到洼地底部,土壤地下漏失模数分别为49.09 t/(km2·a)、212.06 t/(km2·a)、727.71 t/(km2·a)、1104.03 t/(km2·a)、909.11 t/(km2·a),分别占该点年均总土壤侵蚀模数的92.43%、96.24%、78.57%、70.88%和38.68%;不同土地利用方式下的土壤侵蚀存在差异,其土壤侵蚀模数大小依次为坡耕地苦丁茶地苏木林地灌草坡牧草地。通过对该地区水土流失防治及石漠化综合治理,山峰主要涵养水源林、山坡主要发展生态产业防治水土漏失、洼地修建排水系统工程得到良好的效果,治理区土壤侵蚀模数从2003年到2010年下降了65%。     

枣庄市十里泉电厂第三水源地地下水位年变幅灰色预测

该文依据往年地下水位监测数据,通过灰色系统理论的预测模型,对枣庄十里泉电厂地下水位年变幅做出预测,分析了岩溶塌陷发展趋势,为由水动力因素引起的岩溶塌陷地质灾害提供防治依据。     

Coupling multipoint flux mixed finite element methodswith continuous Galerkin methods for poroelasticity

We study the numerical approximation on irregular domains with general grids of the system of poroelasticity, which describes fluid flow in deformable porous media. The flow equation is discretized by a multipoint flux mixed finite element method and the displacements are approximated by a continuous Galerkin finite element method. First-order convergence in space and time is established in appropriate norms for the pressure, velocity, and displacement. Numerical results are presented that illustrate the behavior of the method.     

长江经济带土壤质量评价及产地适宜性初步研究

开展土壤质量评价对科学划定永久基本农田及统筹优化农业生产布局具有重要指导意义。本文采用内梅罗综合污染指数法、分级法、累积频率法和综合判定法,参照《土壤环境质量农用地土壤污染风险管控标准》(试行)(GB 15618—2018)和《绿色食品产地环境质量》(NY/T 391—2013),对长江经济带土壤重金属污染、酸碱度、有益元素丰缺和绿色农产品产地适宜性进行评价。研究区土壤质量总体良好,清洁土壤面积34.84万km²,其重金属含量继承了自然背景特征; 三级及以下土壤面积6.94万km²,呈斑块及星点状分布于赣东北、赣南、湖南长沙—郴州一带、沿江及贵阳、昆明等地,其重金属为自然富集或受矿业开发、煤炭和石油的燃烧及工业“三废”排放的影响。酸性土壤面积33.56万km²,分布于江西、湖南、宁波—台州沿海和金华衢州盆地,碱性土壤面积15.69万km²,分布于苏北平原、环洞庭湖、成都平原以及沿长江一线,其土壤酸碱度与土壤类型有关。土壤有益元素丰缺与第四系沉积物成土母质有关,土壤有益元素适量及以上区域面积34.44万km²,分布于四川阿坝、成都盆地、环洞庭湖、环鄱阳湖、安徽沿江、苏北沿海和杭嘉湖平原; 土壤有益元素缺乏区面积13.89万km²,分布于赣南、江淮、鄂东北以及云南玉溪等地。绿色农产品产地最适宜区、适宜区和不适宜区面积分别为22.49万km²、18.78万km²和18.28万km²。依据区内绿色农产品产地适宜性、土壤环境质量和立地条件划分出7片永久农田保护建议区。     

LA-ICP-MS硅酸盐矿物原位微区分析方法研究

建立了一种利用New Wave UP 213 nm激光和ThermoFisher X Series2四极杆等离子体质谱法直接测定硅酸盐矿物中54种元素的分析方法。该方法以40Ca为内标、玻璃标准参考物质NIST SRM 610为外标,通过调节载气流量、激光频率、激光能量、激光剥蚀斑径降低元素分馏效应,并对NIST SRM 612进行测定,测定结果满足分析要求,54种元素的相对标准偏差大都低于10%,可应用于地质学分析研究。     

A Study on Crack Damage Stress Thresholds of Different Rock Types Based on Uniaxial Compression Tests

When rock samples are loaded until macroscopic fractures develop, the failure process can be divided into several stages based on axial and lateral strain responses or the acoustic emission sequence during uniaxial compression tests. Several stress thresholds may be identified: the crack closure stress σ _cc, crack initiation stress σ _ci, crack damage stress σ _cd, and uniaxial compressive strength σ _ucs; these may be used as a warning indicator for rock rupture. We investigated the crack damage stress σ _cd, its threshold, and a possible relationship between σ _cd and the uniaxial compressive strength. The σ _cd of different rock types were compiled from previous studies based on uniaxial compression tests. The results showed that the overall averages and standard deviations of σ _cd /σ _ucs for igneous, metamorphic, and sedimentary rocks were ~0.78 (±0.11), ~0.85 (±0.11), and ~0.73 (±0.18), respectively. There were no significant differences in σ _cd /σ _ucs between the different rock types, except that the sedimentary rock had a slightly larger standard deviation attributed to the variation of porosity in the samples, while the metamorphic rock had higher average σ _cd /σ _ucs resulting from the small statistical sample size. By excluding the higher-porosity (>10 %) rock samples, the averages and standard deviations of σ _cd /σ _ucs for igneous, metamorphic, and sedimentary rocks were ~0.78 (±0.09), ~0.85 (±0.09), and ~0.78 (±0.11), respectively. The results imply that the rock origin process (i.e., igneous, metamorphic, and sedimentary) has a minimal effect on σ _cd /σ _ucs. The ratio σ _cd/σ _ucs could be an essential intrinsic property for low-porosity rocks, which could be used in rock engineering for predicting the failure process.     

Assessment of the Excavation-Damaged Zone in a Tall Rock Slope Using Acoustic Testing Method

During slope excavation, high stresses can become concentrated in the rock mass because of stress redistribution. Failure of the rock mass creates an excavation-damaged zone (EDZ) in the slope. The damage reduces the acoustic wave velocity in the rock mass. Results of field tests measuring acoustic wave velocity at the Jinping I Hydropower Station are used here to study the EDZ in a tall rock slope. Two acoustic testing methods were adopted in the field tests: single-hole acoustic testing (SAT) and cross-hole acoustic testing (CAT). The acoustic wave velocity was lower in the EDZ, and the depth of the EDZ increased with decreasing slope elevation. Statistical analysis shows that the acoustic wave velocity obtained by the SAT method is larger than that obtained by the CAT method, and the relative difference between the SAT- and CAT-derived velocities is lower for a high quality rock mass than for a low quality rock mass. The integrity ratio and severity of damage can also be determined by acoustic wave velocity test results, revealing that the integrity ratio and elastic modulus of a rock mass are reduced in the EDZ.     

高放废物地质处置北山预选区旧井和新场花岗岩填隙方解石同位素地球化学

为了探讨高放废物地质处置甘肃北山预选区旧井和新场预选地段的古地下流体来源、成因、化学演化历史以及水-岩相互作用,文章系统研究了该地段花岗岩填隙方解石的产出特征及其碳、氧、锶同位素的组成特征。测试结果表明,旧井和新场方解石的δ13 C组成均较稳定且为负值(分别为-11.6‰~-5.7‰和-9.9‰~-5.1‰);δ18 O分别为-0.7‰~19.7‰和10.9‰~21.9‰,旧井方解石具有更宽的δ18 O取值范围。87 Sr/86 Sr也略有差异,旧井为0.708584~0.718749,新场为0.708838~0.732967,二者随深度增加而呈明显的降低趋势。研究表明,北山预选区地下流体来源及成因较复杂,浅部地下水受大气降水的影响较大,深部流体则主要源于地下咸水,为低温流体蚀变成因。花岗岩裂隙中的水-岩反应强度总体较弱,地下水环境相对稳定。相比较而言,新场岩体深部的地球化学环境更稳定,更有利于高放废物的长期处置。     

钻塔喷砂除锈及防腐措施

概述了钻塔喷砂除锈及防腐措施的主要类型、工艺流程、验收评价标准,分析了钻塔喷砂除锈及防腐措施中重要程序和注意事项,对常见的问题给出了处理方案。根据美国石油学会API验收规范标准,结合生产工作实际,对钻塔除锈、喷涂防腐和质量检验进行了分析总结和详细阐述。     

深部开采圆形巷道围岩破损区与支护压力的确定

应用经典塑性力学理论确定的圆形巷道围岩弹塑性应力场存在一些问题,这影响深部圆形巷道的稳定性评价及支护设计的合理性。应用塑性力学求解新体系确定的圆形巷道围岩弹塑性应力场准确解,进行了各向同性均质地层中圆形巷道破损区、地层残余强度与支护压力关系方面的研究,取得了如下成果:(1)破损区随开采深度的增加而增大,它们基本呈线性关系。(2)建立了支护压力与巷道埋深、围岩强度、围岩破坏后残余强度、围岩泊松比和重度之间的关系。研究成果可为支护设计提供重要参考。