不同多孔介质及地下水源热泵运行方式对采能区热贯通的影响

为研究不同多孔介质对地下水源热泵采能区温度场的影响,建立了地下含水层水-热耦合模型,对地下水源热泵在5种多孔介质条件下运行时地下温度场的变化进行了模拟分析,根据发生热贯通的时间及回灌水的温度扩散程度提出了合理井距和优化运行模式。结果表明:在地下水自然横流自抽水井一侧流向回灌井的条件下,细砂最易发生热贯通,其次为中砂、中粗砂,粗砂和砂砾最不易发生热贯通;回灌水热影响半径随着渗透系数增大而减小的明显程度由大到小为粗砂、中粗砂、砂砾、中砂、细砂,但砂砾热影响半径明显小于其他多孔介质;由拟合曲线可得出不同多孔介质在不同渗透系数下的合理井距;以大温差小流量模式运行有助于缓解或避免热贯通,多孔介质为细砂时优化效果更为明显。     

残留含气量影响的非饱和多孔介质流动过程

 多孔介质微观大小孔隙的分布及其连通具有随机性,使得流体在实际孔隙中的流动与理想单孔隙中迥异,当多孔介质中的含水量循环变化时,毛细滞回和残留含气量效应极大地影响着多孔介质的渗流过程。基于对非饱和孔隙介质干湿过程的分析,提出能够考虑残留含气量影响的土水特征关系理论模型,随后建立一个新的渗流理论模型,该模型考虑残留含气量对流动过程的影响。在此基础上,建立相应的数值分析模型,并进行程序代码的实施。建立的模型能够用于模拟任意含水量变化条件下残留含气量对多孔介质中非饱和渗流过程的影响。通过数值模拟结果与实测数据的比较,证实残留含气量效应对非饱和孔隙介质中流体分布的重要影响。为更准确地预测多孔介质中的土水状态,在非饱和渗流分析中考虑残留含气量与毛细滞回效应十分必要。     

有机相变蓄热复合材料导热性能的实验研究

以膨胀多孔石墨(EG)和硅藻土(DI)这2种多孔矿物介质与硬脂酸丁酯(BS)有机相变材料制备了有机相变蓄热复合材料,并采用调制差示扫描量热方法(MDSC)测试了复合材料的导热系数,借助层状复合材料热传导模型分析了多孔矿物介质内部结构特征对复合材料导热性能的影响.结果表明:采用EG和BS制备的有机相变蓄热复合材料具有明显的层状结构,其压制方向的导热系数更接近于层状复合材料热传导模型c轴方向的导热系数;采用DI和BS制备的有机相变蓄热复合材料的导热系数接近层状复合材料热传导模型a-b平面方向的导热系数,即该复合材料内部具有非常好的连通性.多孔矿物介质对有机相变复合材料导热性能的增强效果不仅受多孔矿物介质导热系数的作用,而且还受到复合材料内部结构特征的影响.当复合材料在热传导方向上形成连通性结构时有利于上述增强效果;而当复合材料形成与热传导方向垂直的层状结构时则不利于上述增强效果,即使多孔矿物介质具有很高的导热系数也是如此.     

土遗址墙体含水量与电阻率关系研究

 多孔介质电阻率的影响因素很多,对于特定结构的土遗址墙体,电阻率的变化取决于水分和温度的变化。对交河故城土遗址墙体夯土电阻率模型分析,结合改进的Archie模型,建立特定结构墙体电阻率模型,通过室内电阻率与含水量的关系试验,确定模型公式中的结构参数和土性参数。根据试验建立的墙体电阻率反演含水量关系式,采用高密度电阻率层析法,对交河土遗址现场试验墙体进行尝试性测试。测试结果论证了该模型公式的实用性,为土遗址文物本体水分运移监测中的实际应用奠定基础。     

多尺度条件下ERT视电阻率模型建立及其有效性分析

针对三种不同空间尺度的介质体模型,通过采用数值模拟实测数据的方法,探讨了根据实测数据建立视电阻率模型的方法,并通过与真实电阻率模型对比,分析了视电阻率模型的有效性。结果表明：虽然在数值上视电阻率模型与介质的真实电阻率有较大的偏差,但视电阻率的空间分布格局能够较好的反应真实电阻率的空间分布特征。从而说明建立的视电阻率模型在初步认识介质特性在空间分布上的特征方面是有效的,但要全面了解介质真实电阻率分布特性后期的反演计算仍不可缺少。     

不同介质互层分布的弹性半空间地震波场输入

基于Biot两相饱和多孔介质动力学理论,提出两相饱和多孔介质与单相固体介质互层弹性半空间地震波场解析计算方法,为两相饱和多孔介质和单相固体介质互层分布弹性半空间中的地下结构的地震波场输入提供理论基础。     

多孔介质热质传递国内研究综述

阐述了多孔介质的定义,明确了多孔介质热质传递的重要意义。从萌芽阶段、初级阶段、发展阶段、快速发展阶段4个典型阶段详细介绍了我国多孔介质热质传递研究进展。给出了多孔介质热质传递研究的基本方法和未来的研究方向。为相关学者开展此类研究提供了有意义的理论参考和文献借鉴。     

多孔介质应用于建筑结构的热质传递及制冷性能分析

本文将含湿多孔介质床层应用于建筑围护结构,利用多孔介质内水分蒸发的吸热作用,为房间提供部分冷量。本文在建立非饱和多孔介质热质迁移过程数学模型的基础上,分析了室外环境参数及多孔介质床层结构对床层内温度分布、蒸发量场及水蒸气迁移的影响,为多孔介质蒸发制冷板应用于建筑结构的推广和应用提供了理论指导。     

基于岩土介质三维孔隙结构的两相流模型

地下储层中岩土介质一般具有较低的孔隙连通性,宏观流动模拟一般忽略微观尺度的孔隙连通性,通过渗透率、弯曲度等参数反映储层的整体特性。但岩土介质的多孔性及孔隙间复杂的连通性,使得宏观描述流体在岩土介质中流动不能反映其内在流动特征。孔隙结构模型的建立可以反映岩土介质中孔隙的几何形态及空间连通性,为解释流体在复杂多孔介质中的流动特性提供有效手段。通过考虑岩土介质孔隙尺寸分布、孔隙孔喉空间相关性、孔隙连通性等特征参数,建立了反映不同岩土介质连通性、各向异性特征的等效孔隙网络模型。等效孔隙网络模型通过水力特征参数等效的方式反映岩土介质三维微观孔隙结构,通过渗透率计算验证了模型的有效性。此外,基于建立的孔隙结构模型,开发了孔隙尺度动态两相流计算模型,模型可以反映孔隙内弯液面的动态运动过程,直观反映多孔介质中的优势渗流,可以为不同孔隙尺度岩土介质提供表观渗透率、击穿曲线、相对渗透率曲线等宏观计算参数。将孔隙尺度两相流模型应用于页岩气开采中水力阻滞特性研究,结果表明：页岩基质的残余饱和度约为30%,随着平均配位数的增加,残余饱和度显著降低。     

核废料地质贮存介质黏土岩的三维各向异性热-水-力耦合数值模拟

为了解黏土岩在放射性废料长期贮存中的热-水-力耦合过程,结合MontTerri核废料贮存地下岩石试验工程中黏土岩各种物理量的各向异性特点,应用多孔介质力学耦合理论研究了该黏土岩在加热和冷却全过程中由于热荷载引起的耦合效应场。研究过程考虑温度升高引起的孔隙水黏滞性改变对渗透系数的影响。研究结果表明,岩体力学参数、水力学参数和热传导参数的各向异性特性是影响岩体的温度场、孔隙压力场和应力场分布的最主要因素。各向异性耦合模型与各向同性耦合模型的数值模拟对比研究结果表明：各向异性模型数值结果能更加客观地反映该地下岩石试验工程中黏土岩在受热状态下的热-水-力耦合效应;同时,也表明岩体在加热过程中一直处于受压状态,而在冷却过程中局部会出现拉应力,从而有可能导致拉裂缝的产生。     

Experimental study on the deformation and failure mechanism of overburden rock during coal mining using a comprehensive intelligent sensing method

Understanding the spatiotemporal evolution of overburden deformation during coal mining is still a challenge in engineering practice due to the limitation of monitoring techniques. Taking the Yangliu Coal Mine as an example, a similarity model test was designed and conducted to investigate the deformation and failure mechanism of overlying rocks in this study. Distributed fiber optic sensing (DFOS), high-density electrical resistivity tomography (HD-ERT) and close-range photogrammetry (CRP) technologies were used in the test for comprehensive analyses. The combined use of the three methods facilitates the investigation of the spatiotemporal evolution characteristics of overburden deformation, showing that the mining-induced deformation of overburden strata was a dynamic evolution process. This process was accompanied by the formation, propagation, closure and redevelopment of separation cracks. Moreover, the key rock stratum with high strength and high-quality lithology played a crucial role in the whole process of overburden deformation. There were generally three failure modes of overburden rock layers, including bending and tension, overall shearing, and shearing and sliding. Shear failure often leads to overburden falling off in blocks, which poses a serious threat to mining safety. Therefore, real-time and accurate monitoring of overburden deformation is of great significance for the safe mining of underground coal seams.     

电阻率静力触探测试技术与分析

 首先,简要回顾土的电阻率理论及影响因素,介绍电阻率静力触探测试技术。然后,在归纳相关文献与基于电阻率静力触探现场试验工作的基础上,对电阻率静力触探所测电阻率与土性变化、探头参数及土的其他特性指标进行对比分析。提供的资料表明,电阻率静力触探作为一种快速、经济、可靠的原位测试工具,在评价土的工程特性和预测一些岩土参数是可行的,尤其适用于软土工程的勘察。最后,讨论应用电阻率静力触探测试技术存在的问题,展望电阻率静力触探的研究与应用前景。     

V8可控源音频大地电磁法在铁路隧道不良地质勘察中的应用

铁路隧道不良地质调查是规避施工风险的重要方面,高效快捷的可控源音频大地电磁法利用不同岩性和相同岩性不同辅存结构间所反映的电性特征差异,可以较好地进行围岩级别划分和断裂破碎带判别,为隧道设计和施工提供资料依据。文章结合云桂线铁路定测阶段的施工,选择了灰岩、砂页岩、板岩及含矿围岩等典型地段具体实例,对围岩分级和不良地质体圈定进行了分析,并认为在隧道施工中兼顾矿产资源勘查也是必要的。     

基于电阻率静力触探的海相黏土成因特性分析

土的电阻率是表征土体导电性的基本参数,也是反映土体固有物性的一个综合性指标。众所周知,土的电阻率影响因素较多,因此电阻率随深度的变化可以反映出土体的许多性状。电阻率静力触探(RCPT)作为一种新型的原位测试技术,除可测锥尖阻力、侧壁摩阻力和孔隙水压力以外,还可以同时测试土的电阻率。首先简要介绍了RCPT测试技术,采用电阻率静力触探(RCPT)在连云港海相黏土场地进行了试验,得到土的原位电阻率测试值。结合连云港海相黏土的室内物理化学分析试验,研究了其矿物成分、沉积化学特征,分析了该海相软黏土的电阻率指标与矿物成分、离子含量、胶结特性和氧化环境间的关系。分析表明:基于RCPT测试成果是可以充分反映出连云港海相黏土的成因特性的。     

杭长线相城段岩溶路基的电法物探识别及解释

系统分析了杭州至长沙铁路客运专线相城段岩溶发育的影响因素,通过对不同岩土的电性变化规律进行研究,并结合电法物探的测深法及联合剖面法,分析出相城段岩溶发育的位置及发育规模,最后结合工程钻探资料,验证了电法物探的准确性.     

可控源音频大地电磁测深(CSAMT)攻深找盲探测效果分析——以湖南湘中煤矿资源勘查为例

在分析研究不同地层岩石组成成分、接触关系和对应电性特征基础上,利用可控源音频大地电磁测深来寻找隐伏煤层。已知断裂构造F4为本次探测干扰地质体,采用拉大点距的措施有效避免了由此引起的低阻干扰异常,进一步提高物探异常定性解释可靠性。通过后期钻探验证,在ZK4007号钻孔603.1 m埋深见3.21 m厚煤层;同时,在110.3～150.2 m埋深其灰岩破碎、角砾发育,对岩溶构造推断解释也进行了有效揭露。多个钻探在全覆盖区不同深度发现不同厚度的煤层,有力证明了可控源音频大地电磁测深在全覆盖区进行煤矿资源攻深找盲工作是有效的。     

Geophysical investigations for groundwater in a hard rock terrain,Salem district,Tamil Nadu,India

The main aim of a geophysical investigation in a hard rock region is to solve different hydrogeological problems like depth of water table, basement rock, thickness of weathered zone/formation, structural and stratigraphic conditions relevant to groundwater conditions, and permeability of aquifers. A total of 54 vertical electrode soundings were carried out by Schlumberger electrode arrangement to signify complete lithology of the study area and interpretation was carried out by using curve matching techniques. From the study, 65 % of area is dominated by ‘A’ type curve indicating increasing resistivity with depth and 17 % by ‘K’ type representing a high-resistivity layer sandwiched between two low-resistivity layers. Four layer cases were also noted in 12 % of the study area indicating gradation between the weathered and fractured layers as a semi-weathered zone. Greater thickness has been identified in the weathered zone at the contact of peninsular gneiss and charnockite regions. The maximum, minimum, mean, and arithmetic mean were plotted and identified higher background resistivity values in charnockite. The overlay of maximum and minimum curves for different layers signifies variation of weathering intensity with depth or the presence of weaker zones. In general, lithology plays a significant control over weathering of rocks and groundwater potential.     

Thermal performance modelling of complex fenestration systems

Complex fenestration systems (CFS) have become standard elements in facade design of high performance buildings. They include, for example, shading devices to control illumination, solar heat gains, glare and view-out, and photovoltaic elements imbedded in glazing layers to produce electrical energy on site. However, current methodologies to evaluate the thermal performance of CFS are limited to few products and types. This article develops a general methodology to compute the thermal performance of CFS. The methodology assumes each system layer as porous with calculated effective radiation and thermal properties. A new thermal penetration length model was developed to account for the effects of porous layers on the convective film coefficients of adjacent gas spaces, and applied to various types of shading devices. This methodology is validated using the available measurement and computational fluid dynamics (CFD) simulation results for the U-factor of double-glazed windows with between-pane and internal blinds.     

Effects of slurry on stickiness of excavated clays and clogging of equipment in fluid supported excavations

Mechanized excavation of tunnels and fabrication of deep foundation elements in soft ground often requires a fluid support of the temporarily created openings. The supporting fluids are generally mixtures of bentonite with water, enhanced by chemical additives for difficult geological conditions. The properties of the slurries are chosen to guarantee the stability of the excavation, in particular providing sufficient support to the coarse grained soil layers. When these are interlaid with clayey layers, excavation can be hindered by clogging problems, requiring time consuming cleaning works and causing construction delays. Clogging is caused by the stickiness of the excavated clay, which can be affected both by the clay mineralogy and the composition of the supporting slurry. The paper investigates these effects by means of a laboratory experimental study using novel stickiness tests: the mixing test and a model TBM cutter-head test. For bentonite slurries, the stickiness of the excavated soil was found to correlate with the shear resistance of the slurry. Therefore, increased slurry strength, while beneficial for excavations in coarse soils, may lead to increased susceptibility to clogging under mixed face conditions. In contrast, some pure polymer slurries can help to combine high slurry resistance with low clogging potential by protecting clay aggregate surface from penetration of water.     

张家山矿区矿体赋存特征及可利用性评价分析

结合张家山煤矿的自然地理、地质构造、地层岩性、水文等因素对该矿体进行了圈定,进一步查明该矿体的赋存特征,通过对煤炭的物理性质、煤层特征、化学性能及工艺性能等方面进行分析,对各个煤层的工业用途及其可利用性进行了评价,为以后该煤矿开采提供了地质依据。