Two stages power generation test of the hot dry rock exploration and production demonstration project in the Gonghe Basin,northeastern Qinghai-Tibet plateau,China

The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in efficient drilling and completion,reservoir construction,and fracture simulation.In 2019,China Geological Survey(CGS)initiated a demonstration project of HDR exploration and production in the Gonghe Basin,aiming to overcome the setbacks faced by HDR projects.Over the ensuing four years,the Gonghe HDR project achieved the first power generation in 2021,followed by the second power generation test in 2022.After establishing the primary well group in the initial phase,two directional wells and one branch well were drilled.Noteworthy progress was made in successfully constructing the targeted reservoir,realizing inter-well connectivity,power generation and grid connection,implementing of the real-time micro-seismic monitoring.A closed-loop technical validation of the HDR exploration and production was completed.However,many technical challenges remain in the process of HDR industrialization,such as reservoir fracture network characterization,efficient drilling and completion,multiple fracturing treatment,continuous injection and production,as well as mitigation of induced seismicity and numerical simulation technology.

A study of some Egyptian carbonate rocks for the building construction industry

A number of geotechnical analyses were carried out on selected carbonate rock samples from eight sites located in Egypt. This analysis was to assess the suitability of these rocks for building construction aggregate. The analyses included properties of uniaxial compressive strength, tensile strength, porosity, water absorption, and dynamic fragmentation. The success of building construction depends to a large extent on the availability of raw materials at affordable prices. Raw materials commonly used in the building industry include sands, gravels, clays and clay-derived products. Despite the widespread occurrence of carbonate rocks throughout Egypt, the low premium placed on their direct application in the building sector may be explained in two ways: firstly, the lack of awareness of the potential uses of carbonate rocks in the building construction industry(beyond the production of asbestos, ceiling boards, roof sheets and Portland cement); and secondly, the aesthetic application of carbonate rocks in the building construction depends mainly on their physical attributes, a knowledge of which is generally restricted to within the confines of research laboratories and industries. Thus this paper addresses the physical and mechanical characteristics of some Egyptian carbonate rocks, evaluating them for their suitability as building construction aggregates.

Evaluation and prediction of earth pressure balance shield performance in complex rock strata:A case study in Dalian,China

This research explores the potential for the evaluation and prediction of earth pressure balance shield performance based on a gray system model.The research focuses on a shield tunnel excavated for Metro Line 2 in Dalian,China.Due to the large error between the initial geological exploration data and real strata,the project construction is extremely difficult.In view of the current situation regarding the project,a quantitative method for evaluating the tunneling efficiency was proposed using cutterhead rotation(R),advance speed(S),total thrust(F)and torque(T).A total of 80 datasets with three input parameters and one output variable(F or T)were collected from this project,and a prediction framework based gray system model was established.Based on the prediction model,five prediction schemes were set up.Through error analysis,the optimal prediction scheme was obtained from the five schemes.The parametric investigation performed indicates that the relationships between F and the three input variables in the gray system model harmonize with the theoretical explanation.The case shows that the shield tunneling performance and efficiency are improved by the tunneling parameter prediction model based on the gray system model.

Simulation analysis of construction process of high rock slope's stabilization

A self-developed elasto-plastic finite element program was used to analyze the construction sequence of high rock slope's stabilization in a coal-coking plant, and the result was compared with that employing the ultimate equilibrium method. Based on the results of finite element analysis, the stress contour graphs and displacement vector graphs at different construction steps were obtained, and the behavior of the slope during stabilization construction process was analyzed quantitatively. Based on the analysis of safety factors of three different schemes of stabilization and two different construction schemes, the assessment of stability and bracing design of the construction process were performed. The results show that the original reinforcement design is improper; the stability of the rock slope is controlled by a developed structural plane, the stability factor after excavation is less than 1, and the free surface should be braced in time; for stability, the construction sequence should adopt that bracing follows excavation step by step up to down; the local slide occurred during the construction process agrees with the dangerous slide determined by the numerical analysis, which proves the validity and rationality of the adopted method.

Construction Technology of Large-deformation High Geostress Soft Rock Tunnel

In the process of tunnel construction,if large-deformation occurs in high geostress soft rock,it will likely cause geological disasters.This situation will not only seriously affect the smooth progress of tunnel construction,but also cause serious safety threat to the construction personnel.Therefore,with the continuous growth in the number and scale of tunnel construction in recent years,the construction technology for high geostress soft rock with large-deformation has begun to receive more and more attention from the society.Based on this,this paper takes an actual project as an example to analyze the specific application of the technology in order to improve the construction effect and avoid the damage caused by the large-deformation of the high geostress soft rock.

Non-contact monitoring and analysis system for tunnel surrounding rock deformation of underground engineering

It is very important to monitor surrounding rock deformation in tunnel construction. The principle, function, development and application of the system composed of a total station and computer for monitoring and analyzing surrounding rock deformation were discussed. The new methods of two free station of 3D measurement and its mathematic adjustment mode were presented. The development of software for total station on-board and post for computer were also described. Without centering it and measuring its height, the total station controlled by the software on-board can fulfill the whole measurements to target points. Monitoring data can be processed by the post software and results of regression analysis, forecasting information of the tunnel surrounding rock deformation can be provided in time. The practical use shows that this system is practicable, highly accurate and efficient. It satisfies the needs of safety and information construction in tunnel construction of underground engineering.

Study on the Bioengineering Protection Technique for Rock Slopes in Railway

Ecological protection technique of rock slope is a new slope protection technique,and it is used widely in some supporting engineering of rock slope at railway and highway.But it is always an important research in the field of geotechnical engineering, because the study is related to many subjects and is not systemic and idiographic enough.The paper takes the rock slope of Luozhan(from Luoyang to Zhanjiang)

Some Rock and Soil Mechanical Issues inTGP Construction

The Yangtze Three Gorges Project (TGP) is the key backbone project to develop and harness the Yangtze river in China. As the largest water conservancy project in the world with the earth and rock excavation amounting up to 102.83×10 6 m 3, it is, therefore, the largest project on a scale of geomechanical engineering. The involvement of numerous domestic and foreign research institutes in the scientific research has promoted the development of geomechanics. Some rock and soil mechanical issues arising during construction of the Three Gorges Project are discussed in this article.

Dynamic Risk Assessment Index System for Earth-Rock Dam during Construction

During the construction of earth-rock dam,mutual exclusive construction goals such as quality,safety,progress and cost all have influences on each other,with risk factors being everchanging as the construction progresses.Accurate identification of the risk factors,as well as clearing any possible effect that any risk factors might have on the construction project is the key and foundation to our cooperative control of the construction goals.According to the construction planning of earth-rock dam,the hall3 D structure was used to identify the potential changes of risk factors,and the possible means of any risk factors to interfere with the construction goals.The dynamic risk assessment index system is established by deploying the WBS-RBS(work breakdown structurerisk breakdown structure)method,aiming at the construction goals of earth-rock dam.The case study shows that the index system is very effective at risk management of earth-rock dam during construction,and relatively practicable.

钻孔岩芯基础数据库方案设计及应用——以常熟台为例

针对钻孔岩芯基础数据库构建中钻孔的岩芯试验、数据处理和数据汇集等关键问题,提出钻孔岩芯基础数据库的设计方案。该方案以江苏常熟台钻孔建设施工为例,基于新颁布的《地震台站建设规范地形变台站第2部分:钻孔地倾斜和地应变台站》为施工标准,完成包括钻孔施工流程、岩芯实验步骤和岩芯数据处理分析软件的开发等钻孔岩芯基础数据库的前期关键工作。钻孔岩芯基础数据库的设计方案为钻孔岩芯的收集和试验提供详细的研究思路、方法和实例,填补全国钻孔规范化建设中新增技术指标的空白,为全国钻孔岩芯基础数据库的建设提供参考。

深部破碎软岩巷道超前控顶加固及控制爆破技术

随着矿山开采深度逐渐增加,深部破碎围岩工程地质条件转为复杂多变,极大程度上影响巷道等工程施工过程及后续使用安全;为确保深部破碎软岩巷道施工过程中安全及质量,提出了软岩巷道超前控顶加固及控制爆破技术。针对钟九铁矿-550 m水平6号交岔点岩体裂隙极为发育、稳定性差等特点,拟采用超前控顶措施加固顶板围岩,提高深部破碎软岩巷道的承载力。为便于6号交岔点掘进施工,沿6号交岔点东北侧方向划分17个掘进区,并采用“四步”台阶法分段施工。针对同段起爆数码电子雷管,起爆器系统可随机设置单发雷管起爆间隔时间为3~5 ms,实现同段炮孔单孔单响,降低爆破振动对6号交岔点影响。根据不同掘进区总体岩性情况,优化支护方式(管棚支护、W型钢带及锚索支护等联合支护方式等),确保6号交岔点后续使用期安全。试验结果表明:采用超前控顶加固、控制分区爆破技术,降低破碎软岩巷道顶板偏帮、下沉,保证6号交岔点断面成型效果,削减其支护、后期维护等综合成本达8.7%,该技术可为类似巷道施工提供一定指导建议。

基于质量指标的隧道围岩智能分级及精益建造研究

隧道工程围岩级别的准确判识是围岩稳定性评价及隧道开挖精益支护的基础。围岩质量指标是围岩级别评判的依据,由于围岩质量指标计算包括定性与定量因素,存在定性指标难以准确评定,围岩级别精准评价困难的问题。采用围岩质量指标分级法与机器学习算法融合构建围岩智能分级软件系统,量化分析围岩分级质量指标要素,数值法求解围岩质量指标,围岩级别判定卡采集围岩要素,卡片信息软件系统自动识读、自动分析,快速判定围岩级别,精准确定支护参数,动态优化原支护设计方案。研究成果在3项隧道工程中实践应用,实现隧道围岩精准分级、精益支护建造的目标。

极高地应力硬岩隧道变形规律及施工优化研究

依托重庆市巫镇高速宝山隧道工程,采用数值模拟方法开展极高地应力无仰拱硬岩隧道的变形规律和施工优化研究,对不同施工工法、施工步距进行了比选。研究表明:1)不同施工工法隧道变形规律基本一致,竖向位移大于水平位移且基底隆起较拱顶沉降更明显,全断面法施工隧道变形收敛速度最快;2)不同施工工法均为基底应力释放程度最大,释放后基底应力仅为初始的55%,且全断面法拱脚处应力集中范围最小;3)隧道周围的岩体以拉伸破坏为主,部分位置存在剪切破坏,施工工法对塑性区的水平影响范围有限;4)该隧道选用全断面法施工可行且较经济。全断面法不同施工步距变形及应力分布基本规律相同,施工步距越大,水平竖向位移越大,拱脚处应力集中越显著,最小主应力值也越大,综合考虑现场施工建设速度、变形收敛情况、应力分布状态,采用1.6 m步距较经济合理。

岩棉复合保温外模板承载力及温度效应分析

为了提高建筑外围护结构施工效率及解决传统外保温系统长期存在的易脱落和易着火问题,提出了一种集保温和建筑模板于一体的岩棉复合保温外模板(RW-CIEF)体系。RW-CIEF由内到外依次为内侧加强层、岩棉保温芯材、黏结层、保温过渡层以及外侧加强层。以哈尔滨市为例,基于全寿命周期成本(life cycle cost,C lc)确定了岩棉保温芯材的最佳厚度。采用有限元分析与理论计算相结合的方法探求了RW-CIEF在工程中的可行性,分析了RW-CIEF的抗弯性能、施工承载力及温度效应下的应力和变形,讨论了开槽形式、开槽宽度、开槽深度以及开槽间距对RW-CIEF抗弯性能的影响。结果表明:RW-CIEF的抗弯性能理论计算结果与有限元分析结果有较高的一致性;开槽处理可有效提高RW-CIEF的抗弯性能,综合抗弯性能、热工特性及加工角度,建议开槽形式选用对应开井字槽或对应开纵槽,开槽深度和宽度均为10 mm,开槽间距为150 mm;设计的RW-CIEF满足施工承载力,可保证外围护结构保温工程施工质量;由温度效应产生的最大拉应力和压应力均未超过RW-CIEF的外侧加强层承载力,反映出RW-CIEF出现夏季空鼓或冬季开裂现象的可能性极小。提出的RW-CIEF体系可为外围护结构保温工程及建筑模板工程未来研究方向提供一种新的思路和方法。

断控缝洞型碳酸盐岩立式板状油藏注采井网构建

断控缝洞型碳酸盐岩油藏缝洞结构和连通关系复杂,传统井网部署易产生低产能井,需构建立体注采井网以提高产能。通过油藏数值模拟研究了不同因素对塔里木富满油田满深3和满深4井区立体注采井网波及系数的影响,并设计了先导试验方案预测产能。结果表明,满深3井区注气井与采油井单个交错排状分布时波及系数最大;采油井纵向深度越大,波及系数越大;平面注采井距在500~1000m波及系数相对稳定,井距增至1500m时,波及系数大幅度减小。满深4井区注气井、注水井与采油井单个交错排状分布时波及系数最大。先导试验中,满深3和满深4井区分别采取“浅部注N_(2),深部采油”和“顶部注N_(2),底部注水,中部采油”的井网构建方案,阶段末采出程度分别达到21.3%与22.4%,相比于基础衰竭式开发和注水开发方案有了显著提升。

隧道岩体崩落灾害下施工人员疏散模拟方法研究

在隧道工程建设过程中,岩体崩落等安全事故属于常见的危险情况。为能够综合考虑到岩体坍塌这类动态危险障碍物对隧道内施工人员应急疏散的影响,选取某高原地区铁路隧道工程作为研究对象,运用元胞自动机理论(CA)构建了隧道内人员与动态危险障碍物(如落石)轨迹交互模型,并研发了岩体崩落时的人员疏散模拟方法。在此基础上,对隧道内不同岩体崩落灾害等级和范围下的应急疏散过程进行了分级分段的数值模拟和讨论。结果表明:开发的数值模拟方法能够准确地模拟出不同灾害等级下人群在岩体崩落时的疏散过程和伤亡情况;根据模拟结果可知,当发生同一等级的岩体崩落事故时,随着灾害范围的扩大,受伤人数增加,整体疏散速度变慢,从而导致疏散时间延长;同时,灾害等级也是影响施工人员安全的主要因素,灾害等级越高,坍塌岩块的密度越大,从而增加了临灾群体受伤和死亡的概率。该疏散模型为隧道灾害条件下施工人员应急疏散提供了参考依据。

超大规模硬岩矿山源头推动TBM应用的设计创新与思考

西鞍山铁矿是一座超大规模开采矿山,采用TBM施工胶带斜井、斜坡道是该技术在国内地下铁矿山首次应用。TBM施工与钻爆法施工在勘察、设计和施工等方面均有较大差异,本文基于应TBM施工铁矿井巷工程,结合设备性能与开拓系统工艺需求,在斜井线路规划、曲线半径选择、始发场地设计、始发段与接收段支护、正常段支护选型、巷道底板处理、硐门设计形式等开展了应用创新。同时结合项目设计、施工中遇到的问题,对适用于矿山工程的TBM施工勘察技术要求、施工方案的选择及提高TBM施工断面利用率进行了分析与探讨。

生态库区超厚硬岩条件下大直径长桩桩基施工关键技术

针对生态库区超厚硬岩条件桥梁大直径长桩相对复杂的施工环境,常规施工工艺易造成环境污染、硬岩地层钻进速度慢、维护费用高。为了保护环境也方便施工,提出一种桩基新型施工技术,通过潜孔锤和旋挖钻结合,高效快速完成桩基施工且绿色环保。依托工程实例,对相关施工工艺进行详细阐述。

三维逆向重构技术在地质教学中的应用——以节理面力学性质教学为例

讲授岩石结构面的力学性质,是地质专业人才培养的必要环节。然而,传统的教学方式如板书教学、图片展示、动画制作等,都不足以让学生深刻全面地了解结构面在岩石强度中的影响机理。随着计算机技术的发展,三维逆向重构技术使高精度复刻结构面成为可能。为更加充分地满足课程教学需求,使学生能够在实践中对结构面抗剪机理有更加深入的了解,该文将三维光学扫描技术、计算机模型构建技术、3D打印技术用于课堂教学实践,对传统教育方法做进一步改进。

浅埋河谷段TBM施工应用与适宜性评价

TBM施工技术应用于隧洞开挖,技术上已经成熟,并广泛应用于深埋长大隧洞施工中。影响隧洞TBM施工的因素基本清楚,一般认为穿越浅埋河谷段隧洞采用TBM施工容易发生围岩塌方、涌水事故,不适宜采用TBM施工。为了研究浅埋河谷段TBM施工适宜性,通过两个典型的穿越浅埋河谷段隧洞TBM施工的工程实例,对比详细的工程地质条件,分析塌方的原因,进行TBM施工适宜性分析,结果表明,隧洞上覆弱风化岩体大于1倍洞径段进行适当的工程处理后,采用TBM施工是适宜性的。