基于随机分析的滑坡稳定性二元评价方法

对利用随机分析方法建立安全系数与可靠性相耦合的滑坡稳定性二元评价体系进行了探索。利用随机分析方法可确定滑坡安全系数的分布形态,计算出最大可能安全系数下的滑坡破坏概率P_f,用最大可能安全系数和可靠性得出可靠安全系数来评价该滑坡的稳定性。在折减后的安全系数的极限状态中,根据典型的不同最大可能安全系数及相应的临界破坏概率,建立了二元滑坡稳定性分区,用于滑坡稳定性评价。研究实例表明:利用随机分析方法建立这种二元体系是可行的,可以更加精确和客观的对滑坡稳定性做出评价。      

双频激电法在山区复杂条件下的应用——以福建垄源金多金属矿区为例

双频激电法可同时得到低频和高频电位差,由其计算视幅频率可抵消相同的影响因素,抑制干扰,增强异常幅值,提高观测精度。根据垄源金多金属矿区物性参数可确定受构造控制的硫化多金属矿（脉）体多以充填形式产出,具有低阻高极化反映,随着埋深的不同,视幅频率（Fs）有相应的变化,幅值一般为4%～11%,与背景视幅频率（Fs）2%～4%有明显差别。该区野外工作采用SQ-3C双频激电仪器,测网布设测线6条,其中线距100m、点距10m、、测线长度为400m。根据Fs、ρs曲线形态及Fs等值线图解释该矿区存在一条破碎带,破碎带北部呈现矿体异常特征,推断矿体（脉）走向为北西—南东向。依据该物探成果结合地质资料,布置钻探验证孔,其中8-1孔于156m见导水断裂破碎断层,8-2孔于31m见高品位金多金属矿（脉）体,验证物探解释与地质钻探吻合。     

磁铁矿与黄铁矿双向交代研究及意义

在华北盆地南缘早古生代碳酸盐岩中,发现了包括交代假象和交代残余枯内的一系列足以支持磁铁矿与的矿之间发生双向交代作用的确凿矿物学证据,甚至在同一个磁性矿物颗粒内,还辨认出方向完全相反而且是先后发生的２种交代现象。磁铁矿（铁磁性矿物）和黄铁矿（顺磁性矿物）之间有双向交代会直接干扰古地磁数据,并影响以此为基础而开展的地块运动分析和古地理的重建。     

不连续面在双重介质热-水-力三维耦合分析中的有限元数值实现

在建立双重介质热-水-力耦合微分控制方程的基础上,提出了裂隙岩体热-水-力耦合的三维力学模型,对不同介质分别建立以节点位移、水压力和温度为求解量的三维有限元格式,开发了双重介质热-水-力耦合分析的的三维有限元计算程序,在有限元数值分析中不连续面应力计算采用等厚度空间8节点节理单元进行离散,而不连续面渗流和热能计算时采用平面4节点等参单元进行离散,这样保证了不同介质之间的水量、热量交换和两类模型接触处节点水头、温度和位移相等。通过高温岩体地热开发算例,揭示了在热-水-力耦合作用下不连续面处于低应力区,其张开度随运行时间的延长呈非线性增加,非稳定渗流阶段不连续面显著地控制着渗流场的整体分布,它的水头远高于拟连续岩体介质的水头,而进入稳定渗流阶段不连续面的控渗作用不明显,由于高温岩体地热开发系统中存在大规模的热量补给,不连续面对岩体温度场分布的影响并不显著。     

Dual Control of Depositional Facies on Uranium Mineralization in Coal‐bearing Series: Examples from the Tuanyushan Area of the Northern Qaidam Basin,NW China

The uranium deposits in the Tuanyushan area of northern Qaidam Basin commonly occur in coal-bearing series. To decipher the U-enrichment mechanism and controlling factors in this area, a database of 72 drill cores, including 56 well-logs and 3 sampling wells, was examined for sedimentology and geochemistry in relation to uranium concentrations. The results show that coal-bearing series can influence uranium mineralization from two aspects, i.e., spatial distribution and dynamic control. Five types of uranium-bearing rocks are recognized, mainly occurring in the braided river and braided delta sedimentary facies, among which sandstones near the coals are the most important. The lithological associations of sandstone-type uranium deposits can be classified into three subtypes, termed as U-coal type, coal-U-coal type, and coal-U type, respectively. The coal and fine siliciclastic rocks in the coalbearing series confined the U-rich fluid flow and uranium accumulation in the sandstone near them. Thus, the coal-bearing series can provide good accommodations for uranium mineralization. Coals and organic matters in the coal-bearing series may have served as reducing agents and absorbing barriers. Methane is deemed to be the main acidolysis hydrocarbon in the U-bearing beds, which shows a positive correlation with U-content in the sandstones in the coal-bearing series. Additionally, the δ13 C in the carbonate cements of the U-bearing sandstones indicates that the organic matters, associated with the coal around the sandstones, were involved in the carbonation, one important component of alteration in the Tuanyushan area. Recognition of the dual control of coal-bearing series on the uranium mineralization is significant for the development of coal circular economy, environmental protection during coal utilization and the security of national rare metal resources.     

Petrochemical constraints for dual origin of garnet peridotites from the Dabie-Sulu UHP terrane, eastern-central China

Garnet peridotites occur as lenses, blocks or layers within granulite–amphibolite facies gneiss in the Dabie-Sulu ultra-high-pressure (UHP) terrane and contain coesite-bearing eclogite. Two distinct types of garnet peridotite were identified based on mode of occurrence and petrochemical characteristics. Type A mantle-derived peridotites originated from either: (1) the mantle wedge above a subduction zone, (2) the footwall mantle of the subducted slab, or (3) were ancient mantle fragments emplaced at crustal depths prior to UHP metamorphism, whereas type B crustal peridotite and pyroxenite are a portion of mafic–ultramafic complexes that were intruded into the continental crust as magmas prior to subduction. Most type A peridotites were derived from a depleted mantle and exhibit petrochemical characteristics of mantle rocks; however, Sr and Nd isotope compositions of some peridotites have been modified by crustal contamination during subduction and/or exhumation. Type B peridotite and pyroxenite show cumulate structure, and some have experienced crustal metasomatism and contamination documented by high ⁸⁷Sr/⁸⁶Sr ratios (0.707–0.708), low ε_Nd( t ) values (−6 to −9) and low δ¹⁸O values of minerals (+2.92 to +4.52). Garnet peridotites of both types experienced multi-stage recrystallization; some of them record prograde histories. High- P–T  estimates (760–970 °C and 4.0–6.5±0.2 GPa) of peak metamorphism indicate that both mantle-derived and crustal ultramafic rocks were subducted to profound depths >100 km (the deepest may be ≥180–200 km) and experienced UHP metamorphism in a subduction zone with an extremely low geothermal gradient of <5 °C km⁻¹.     

吉林省长白山天池新生代火山喷发作用及火山灾害的环境效应

通过对吉林省长白山天池火山的研究及１：５万区域地质调查资料,将区内新生代上新世以来的火山活动划分为４个火山喷发旋回及１３个火山喷发期,对爆发性火山作用划分了岩浆型、蒸气－岩浆型（岩浆－蒸气型）和蒸气型三种类型。火山喷发动力学机制的研究,对长白山天池火山的稳定性作出补步评价,在此基础上,对该区生代上新世以来的火山喷发作用及其引发的火山灾害的环境效应进行了论述。并对火山喷发作用所产生的积极环境效应,提出了合理开发和利用的建议。     

双主卷扬配合“环形道活门机构”的快速提下钻系统

为了提高快速提升钻具更换钻具的能力,研制了SPT-600D型拖车钻机。该钻机配置了SPS-600型双卷扬钻机及“环形道活门机构”。试验及应用情况表明,双卷扬配合“环形道活门机构”能够快速提升钻具更换钻具,缩短钻井施工的时间,可实现水文水井施工优质、高效、快速的要求。     

双时间步法在二维浅水方程求解中的应用

针对传统算法效率低的问题,将隐式双时间步法应用于求解二维浅水方程,建立了非结构网格下高效的有限体积模型。在应用双时间步法时,虚拟时间层中的定常问题采用高效的隐式LU-SGS（Lower-Upper Symmetric Gauss-Seidel）方法进行迭代求解。通过模拟计算4个典型算例以及与传统显式算法进行比较,对模型精度、效率及处理实际问题能力进行检验,分析了时间步长、内迭代次数对模型性能的影响。结果表明,双时间步法放宽了稳定性对时间步长的限制,时间步长可取到显式格式10倍以上,计算耗时减少了50%以上,模型具有良好精度与适应性,具有较好的推广应用价值。     

相控阵天气雷达监测预警龙卷风的过程剖析

天气雷达作为龙卷风监测预警的重要手段之一,应用具有超高时空分辨率的X波段双极化相控阵天气雷达系统,较好地捕获并提前预警龙卷风。以2022年6月19日07时发生在广东佛山南海的一次龙卷风为例,详细剖析龙卷生消及雷达监测预警过程。借助雷达智能预警软件,利用X波段双极化相控阵天气雷达的双偏振量和超高时空分辨率数据,实时反演三维风场和分析龙卷碎片(TVS)特征,能够显著提高龙卷风监测预警水平。实例表明,本次成功地提前18分钟预警龙卷,进一步说明了X波段双极化相控阵天气雷达在强对流天气探测方面具有较强的生命力。