土工格栅加筋膨胀土渠坡数值模拟研究

对土工格栅加筋膨胀土渠坡这种较新的膨胀土处理措施进行研究,在考虑土工格栅与填土之间的相互作用、膨胀土吸水膨胀、软化特性等膨胀土渠坡关键影响因素的基础上,提出了土工格栅加筋膨胀土渠坡数值计算的新思路,并采用有限差分软件Flac3D进行了验证。数值算例结果表明,土工格栅对膨胀土渠坡有明显的水平位移约束作用,是有效的处理措施,可以在实际工程中采用。     

模糊方法在地质灾害危险性评价中的应用

地质灾害评估是协调人地关系研究的重要内容,可为大型工程建设的前期工作提供基本依据。本文采用模糊综合评价法,选择历史灾害危险性、潜在灾害危险性2个基本要素和相应的8个评价因子,对甘肃省洮河莲麓水电站建设用地地质灾害危险性进行了评估。结果表明:河谷地貌区和山间盆地地貌区地质灾害危险性中等,中山地貌区地质灾害危险性小。     

“十三五”期间中国探矿权及地质勘查投资时空演变

基于详细的统计数据,从时间、空间、结构等多个纬度,对中国探矿权及地质勘查投资情况进行了时间序列、因素相关性等对比分析和综合研究,为政府管理部门制定政策和规划提供参考依据。通过研究,揭示了影响探矿权及地质勘查投资的主要因素、底层逻辑和发展规律,并认为受国内外宏观经济增速放缓、地缘政治等因素影响,特别是国内相关产业政策、生态和环境保护压力,“十三五”期间中国探矿权数、地质勘查投入和新发现矿产地持续大幅度减少。“十三五”期间,新立探矿权同比减少52.1%,注销探矿权数是“十二五”期间的3.7倍多。油气矿产的探矿权登记面积和地质勘查投资分别占全国的96%和77.6%;非油气矿产探矿权数占全国的90%以上,有近60%的非油气探矿权在西部地区;非油气地质勘查投资中,水工环及科技等投资额占居半壁江山。预计中国在能源矿产、战略性矿产等勘查领域将增加勘查投入,地质勘查投资将于2024年后逐渐走出低谷。     

辽东兰花岭地区古元古代I型花岗岩类与辽吉A型花岗岩对比研究

辽东半岛是华北克拉通胶-辽-吉古元古代活动带的重要组成部分,古元古代经历了复杂的构造演化过程,并记录了多期岩浆-变质作用,约2.2 Ga的辽吉A型花岗岩和1.89~1.85 Ga的巨斑状花岗岩、正长岩分别标志着辽东古元古代造山作用的开端和结束。最新研究显示,2.20~2.15 Ga的岩浆作用形成了2种不同类型的花岗岩,它们可能具有不同的岩石成因和构造意义。在青城子铅锌矿集区北部采集的兰花岭、白砬子花岗闪长岩和黄泊辉绿岩,锆石U−Pb年龄分别为2177±19 Ma、2129±36 Ma、1876±29 Ma。花岗闪长岩的岩石成因类型、地球化学特征与典型的约2.2 Ga的辽吉A型花岗岩明显不同,属于弱过铝质、低钾钙碱性—碱性岩石,Zr、Hf、Nb、Rb含量较低,K2O/Na2O值、稀土元素总量极低,为典型的I型花岗岩类。根据锆石Lu−Hf同位素分析,εHf (t)值为−5.1~9.0,二阶段Hf模式年龄tDM2为2089~2817 Ma,岩浆源区为约2.5 Ga的太古宙地壳物质和少量软流圈地幔物质。兰花岭地区花岗闪长岩具备岛弧或活动大陆边缘的地球化学亲缘属性,可能形成于弧岩浆俯冲挤压环境;结合形成于伸展环境的A型条痕状花岗岩特征,认为约2.2 Ga辽东地区古元古代活动带呈现总体伸展、局部挤压的构造环境,为洋壳板块向龙岗地块俯冲碰撞过程中或碰撞后的弧后盆地。     

中国煤层气资源控制程度及可靠性分析

准确认识深部条件下气体和水分的赋存状态、相对含量及分布特征,对煤层气高效勘探开发具有重要指导意义。基于理论模型、分子模拟和气水演变分析,明确了煤层中气、水的赋存状态,揭示了气、水动态运聚界限和动态演化过程。考虑煤−水界面作用、水的可动性及赋存状态,煤中水可分为可动水(重力水和毛细水)、束缚水(吸附水、沸石水、结晶水和层间水)、结构水,其中毛细水、重力水和吸附水由孔隙主导,沸石水、结构水、结晶水和层间水由矿物主导。分子模拟结果显示,水分子在0.7 nm孔隙中可以饱和充填,吸附和解吸路径一致,在更大孔隙中出现弱吸附层和自由态。水分子吸附过程表现为单分子含氧基团吸附、单层强吸附、多层弱吸附、水团簇形成和充填孔隙等阶段。甲烷分子在1.5 nm孔隙可存在3层稳定充填吸附,在较大孔隙中(>1.5 nm)即以单层吸附和游离态共存,游离态在介孔及更大孔隙中普遍存在。结合上述吸附−游离气存在界限,改进了游离气和吸附气理论计算公式,为含气量计算提供新思路。深部热成因煤层气是煤大规模生排烃之后的残余气,在排烃过程中发生气驱水和水分蒸发扩散,残余水分为束缚水和结构水,后期无法改变。假定静水压力20 MPa,在0、5、10、15和20 MPa储层压力下,外来水分可入侵最大孔径为7、9、13、27 nm和不侵入。受差异保存条件控制,煤成气除了形成超压和欠压等差异含气系统外,还可能在煤系形成多类型含气模式。上述研究明确了煤层气、水微观赋存机制及形成演化模式,对深部煤层气富集特征及高效开发设计具有指导意义。

     

高硫酸盐矿山废水的处理方法研究进展

高硫煤矿闭坑后成为埋藏在地表以下深部的产酸污染场,对相邻含水层和周边环境造成了潜在危害,且因采动效应影响和矿井空间分布复杂导致相邻含水层的污染过程与污染程度评价困难。以某闭坑矿区为研究对象,选取SO₄ ²⁻作为特征污染物,考虑多煤层采动裂隙对含水层结构的破坏影响,运用数值模拟技术对闭坑矿区酸性矿井水中SO₄ ²⁻污染迁移特征进行研究,并分析流体扩散系数对含水层污染物运移的影响。结果表明：SO₄ ²⁻在二叠系童子岩组砂岩含水层中水平迁移面积随时间增大而增大,增大速率逐渐减小,垂向渗透系数扩大10倍,空间变异性增强;闭坑5、10、15 a后,最大水平迁移距离分别为215、414、612 m,最大垂向迁移距离分别达到50、65、70 m;而扩散系数越大,产酸时间越长,SO₄ ²⁻迁移距离和污染范围将随之增大,相较于水平方向,垂向上SO₄ ²⁻浓度变化对扩散系数的敏感度更高。基于模拟结果,结合闭坑矿区实际条件,针对性提出了“源头减量−过程阻断−末端治理”的综合防控与治理方案。研究结果将为该闭坑煤矿酸性矿井水污染治理与防控提供理论基础,也为其他同类矿井提供科学借鉴。

     

Validity of the Bouchet’s complementary relationship at 102 observatories across China

Bouchet in 1963 hypothesized that for large homogeneous land surface with minimum advection of heat and moisture, there exists a 1:1 complementary relationship of potential and actual evaporation coupled through land-atmosphere feedbacks. The complementary relationship has been widely used to estimate regional actual evaporation and explain the pan evaporation paradox. We examine the standardized potential evaporation (potential evaporation divided by wet environment evaporation) at 102 observatories at different elevations across China. Generally, the relationship is appropriate at the low elevations (<1000 m). With the increase of elevation, vapor transfer power becomes much less than radiation energy budget because of lower vapor pressure deficit and stronger global solar radiation. As a result, at the high elevations (over 1000 m), the excess energy resulted by limited moisture availability is not enough to be converted into drying power of the air. This result suggests that the complementary relationship is asymmetric at the high elevations. Supported by the Presidential Special Award Foundation, the Chinese Academy of Sciences (Grant No. O7R70020SD) and the National Key Technology R & D Program (Grant No. 2006BAC08B0408)     

The prospects for modernizing very broadband seismometers

This paper considers the possibilities for modernizing the KSESh broadband seismic station developed earlier at the IPE AS USSR. The goal of the modernization was to extend the frequency and dynamic ranges and to decrease nonlinear distortions. The ways and concrete methods for improving the mechanical construction and electronic components of the station are shown and the intermediate results are described. As preliminary estimates show, there is an opportunity to build devices with the velocimeter response up to 520–540 s periods on the basis of this pendulum.     

水泥粉煤灰碎石桩复合地基抗震性能分析

水泥粉煤灰碎石桩（简称ＣＦＧ桩）是近年来开发的一种地基处理新方法。这种桩能充分利用工业废渣废料,其受力特性类似混凝土柱,很有潜力,值得推广应用。但是在地震区域,褥垫层成为上部结构和地基基础之间的一个薄弱层,因此在地震区加强上部结构与地基基础的整体刚度,改善ＣＦＧ桩的抗震性能是非常重要的。     

Possibilities of interpretation of the magnetotelluric data,obtained on a single profile over 3D resistivity structures

Magnetotelluric soundings are frequently carried out on a single profile or on profiles remote from each other. Interpretation of the obtained data is difficult in the presence of spatially heterogeneous geoelectric structures. We evaluate its capabilities on the basis of the synthetic data, that correspond to a geoelectric model, which consists of a three-layered section in the background and three rectangular prisms, differently arranged relative to the profile. Using the simple methods of analysis of magnetotelluric data, we succeeded in allocating all three heterogeneities over the area that surrounds the profile of observations. As a result of the fast smoothed-structure 1D and 2D inversion of different components of data, taking into account their specific features, the depths of the occurrence of anomalies and the order of the values of their electrical resistivity were evaluated, and the background section was also reconstructed. On this basis, and, also, with the use of a priori geological-geophysical information, the construction of a 3D model in a more or less broad band around the profile and its correction with the aid of 3D data inversion are possible.