钢筋混凝土长肢一字形截面柱抗震性能试验研究

对4个1／2缩尺的长肢一字形截面柱构件进行了低周反复荷载下的抗震性能试验研究,构件截面高厚比分别为4．0、4．5与5．0,分别按柱子配筋与按剪力墙配筋两种配筋方式进行设计。通过试验分析了长肢一字形截面柱的承载力、刚度、延性、耗能、滞回特性等,并提出了抗震设计建议。     

基于极限学习自编码器的水声信号目标识别方法

传统的机器学习方法在特征提取时容易受到主观经验的影响,导致对水声信号目标的识别准确率不高。而一般深度学习算法模型较复杂,通常具有训练耗时、计算复杂度高等缺点。极限学习自编码器具有很强的非线性处理能力,适合针对具有非线性特点的水声信号目标的识别,而且模型具有学习速度快,泛化能力强等显著优势。将极限学习自编码器算法应用于水声信号目标识别中,并与卷积神经网络、自编码器和极限学习机识别方法进行对比,结果表明：提出的方法对水声信号目标识别的准确率最优,且训练时间较短。     

基于钻进状态监测的智能工况识别

钻进过程状态监测旨在实时描述钻进工况,判断运行性能优劣程度进行非优追溯,及时指导司钻人员调整作业操作,保证钻进过程安全、高效、稳定开展。钻进工况是钻进系统运行状态的反映,因此开展面向状态监测技术的钻进工况识别研究具有重要的理论和应用价值。本文针对钻进工况识别问题,基于状态监测数据,建立基于支持向量机的钻进工况识别模型,对钻进工况进行识别。综合工况识别结果,对钻进效率进行评估,并对影响钻进效率的因素进行讨论,寻找提升钻进效率的手段。最后,采用钻进现场实钻数据进行仿真实验,验证所提方法的可行性和有效性。     

插拔桩靴对临近桩靴承载力的影响研究

自升式钻井船桩靴的插拔过程将会对临近井口平台的桩靴基础产生不利影响。开展了室内模型试验研究,将试验结果与理论分析结果相结合,得到了桩靴插拔的影响范围及影响范围内土体强度的变化规律,并推导了桩靴插拔影响区内临近桩靴承载力的计算方法,与模型试验结果进行了对比验证。研究表明,桩靴插拔后砂土相对密实度降低,其降低程度随距桩靴距离的增加而逐渐减小,影响范围约为1倍桩靴直径。受桩靴插拔影响,临近桩靴的承载力下降,降低比例随两桩靴相对间距的增大而减小,随桩靴相对插深的增加而增加。当两桩靴相对间距大于2倍插拔桩靴直径时,可认为桩靴插拔对临近桩靴基础承载力无影响。     

Spatial Characteristics and Controlling Factors of the Strike‐slip Fault Zones in the Northern Slope of Tazhong Uplift,Tarim Basin: Insight from 3D Seismic Data

The detailed characteristics of the Paleozoic strike-slip fault zones developed in the northern slope of Tazhong uplift are closely related to hydrocarbon explorations. In this study, five major strike-slip fault zones that cut through the Cambrian-Middle Devonian units are identified, by using 3D seismic data. Each of the strike-slip fault zones is characterized by two styles of deformation, namely deeper strike-slip faults and shallower en-echelon faults. By counting the reverse separation of the horizon along the deeper faults, activity intensity on the deeper strike-slip faults in the south is stronger than that on the northern ones. The angle between the strike of the shallower en-echelon normal faults and the principal displacement zone(PDZ) below them is likely to have a tendency to decrease slightly from the south to the north, which may indicate that activity intensity on the shallower southern en-echelon faults is stronger than that on the northern ones. Comparing the reverse separation along the deeper faults and the fault throw of the shallower faults, activity intensity of the Fault zone S1 is similar across different layers, while the activity intensity of the southern faults is larger than that of the northern ones. It is obvious that both the activity intensity of the same layer in different fault zones and different layers in the same fault zone have a macro characteristic in that the southern faults show stronger activity intensity than the northern ones. The Late Ordovician décollement layer developed in the Tazhong area and the peripheral tectonic events of the Tarim Basin have been considered two main factors in the differential deformation characteristics of the strike-slip fault zones in the northern slope of Tazhong uplift. They controlled the differences in the multi-level and multi-stage deformations of the strike-slip faults, respectively. In particular, peripheral tectonic events of the Tarim Basin were the dynamic source of the formatting and evolution of the strike-slip fault zones, and good candidates to accommodate the differential activity intensity of these faults.     

湖南鲁塘煤系石墨矿区构造格局及控矿机制

湖南鲁塘矿区为我国著名的煤系石墨矿区,煤系石墨的形成受岩浆热作用和构造作用的双重控制,其成矿和赋存都与构造格局密切相关。为深入研究构造作用对煤系石墨成矿的影响,通过野外地质调查和光学显微镜下观察、X射线衍射和拉曼光谱等测试分析方法,分析研究区构造特征和煤系石墨特征。研究结果表明,受区域构造活动的影响,鲁塘矿区构造格局呈现出分区分带性特征,东西方向可划分为东部、中部和西部3个条带;南北方向可划分为北部、中部和南部3个分区。自西向东,随着与岩体距离逐渐减小,煤层受岩浆热作用的影响逐渐增大,煤的石墨化程度也逐渐增高。由南向北,构造变形强度逐渐增强,导致北部分区形成以封闭式高温-高压的成矿环境为主,同时,应力作用促进了煤的石墨化,导致煤的石墨化程度较高;中部分区内构造情况复杂,形成不同温度压力条件的成矿环境,煤的石墨化程度差异性明显;南部分区构造情况简单,主要构成开放式环境,煤的石墨化程度较低,仅在近岩体附近可形成煤系半石墨。研究成果为煤系石墨资源勘探提供了有力依据。      

福建大田—漳平地区构造-热对煤系石墨成矿及赋存的控制探讨

福建省大田—漳平地区位于东部滨太平洋构造带上,不同时期的岩浆热液作用和复杂多变的构造形变格局,为该地区形成丰富的石墨矿床提供了良好的成矿条件。为了查明大田—漳平地区煤系石墨的成矿控制因素及分布规律,通过工业分析、元素分析、X射线衍射和激光拉曼光谱等实验,对不同矿区不同变质程度的煤和煤成石墨的化学组成及微观结构特征等煤成石墨化特征进行了研究,并将不同变形特征的样品划分为煤成石墨、煤成半石墨和石墨化无烟煤三大类。研究表明:煤的变形特征与煤成石墨的演化类型基本一致,且韧性变形样品的石墨化程度最高,说明构造应力作用能促进煤的石墨化作用;煤成石墨的分布受到岩浆-构造活动的控制,石墨矿床多产出于岩浆岩侵入体外接触带或附近断裂带的有利围岩地层中,且大田—漳平地区煤系石墨矿具有明显的成区、成带分布特点,煤成石墨成矿区主要集中在闽西南坳陷南部的漳平一带;而北部大田一带分布的矿区矿体石墨化程度较漳平一带低,多为煤成半石墨或石墨化无烟煤,研究结果可为该地区煤系石墨矿产综合勘探开发利用提供有利依据。      

The Early Permian Woniusi Flood Basalts from the Baoshan Terrane, SW China: Petrogenesis and Geodynamic Implications

The Woniusi flood basalts from the Baoshan terrane, SW China, represent a signi?cant eruption of volcanic rocks which were linked to the Late Paleozoic rifting of the Cimmeria from the northern margin of East Gondwana. However, the precise mechanism for the formation and propagation of the rifting is still in debate. Here we report 40Ar/39Ar dating, whole-rock geochemistry, and Sr–Nd–Pb isotopes for the Woniusi basalts from the Baoshan terrane of SW China, with the aim of assessing if a mantle plume was related to the formation of the continent Cimmeria. 40Ar/39Ar dating of the Woniusi basalts yielded ages of 279.3 ± 1.1 Ma and 273.9 ± 1.5 Ma, indicating they were emplaced during the Early Permian. Whole-rock geochemistry shows that these basalts have subalkaline tholeiitic af?nity, low TiO2 (1.2–2.2 wt%), and fractionated chondrite-normalized LREE and nearly ?at HREE patterns [(La/Yb)N = 2.86–5.77; (Dy/Yb)N = 1.21–1.49] with noticeable negative Nb and Ta anomalies on the primitive mantle-normalized trace element diagram. The ?Nd(t) values (?4.76 to +0.92) and high (206Pb/204Pb)i (18.40?18.66) along with partial melt modeling indicates that the basalts were likely derived from a sub-continental lithospheric mantle (SCLM) source metasomatized by subduction-related processes. On the basis of a similar emplacement age to the Panjal basalts and Qiangtang mafic dykes and flood basalts in the Himalayas, combined with a tectonic reconstruction of Gondwana in the Early Permian, we propose that the large-scale eruption of these basalts and dykes was related to an Early Permian mantle plume that possibly initiated the rifting on the northern margin of East Gondwana.     

Coalbed Methane Enrichment Regularity and Major Control Factors in the Xishanyao Formation in the Western Part of the Southern Junggar Basin

There are abundant coal and coalbed methane(CBM)resources in the Xishanyao Formation in the western region of the southern Junggar Basin,and the prospects for CBM exploration and development are promising.To promote the exploration and development of the CBM resources of the Xishanyao Formation in this area,we studied previous coalfield survey data and CBM geological exploration data.Then,we analyzed the relationships between the gas content and methane concentration vs.coal seam thickness,burial depth,coal reservoir physical characteristics,hydrogeological conditions,and roof and floor lithology.In addition,we briefly discuss the main factors influencing CBM accumulation.First,we found that the coal strata of the Xishanyao Formation in the study area are relatively simple in structure,and the coal seam has a large thickness and burial depth,as well as moderately good roof and floor conditions.The hydrogeological conditions and coal reservoir physical characteristics are also conducive to the enrichment and a high yield of CBM.We believe that the preservation of CBM resources in the study area is mainly controlled by the structure,burial depth,and hydrogeological conditions.Furthermore,on the basis of the above results,the coal seam of the Xishanyao Formation in the synclinal shaft and buried at depths of 700-1000 m should be the first considered for development.