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Prediction of lining response for twin tunnels constructed in anisotropic clay using machine learning techniques

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Underground Space 2022年第1期7卷 122-133页

作者： Wengang Zhang Yongqin li Chongzhi Wu hongrui li ATC Goh Hanlong liu School of Civil Engineering Chongqing UniversityChongqing 400045China National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas Chongqing UniversityChongqing 400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing 400045China School of Civil and Environmental Engineering Nanyang Technological UniversitySingapore

Excessive structural forces generated inside tunnel linings could affect the safety and serviceability of tunnels,emphasizing the need to accurately predict the forces acting on tunnel linings during the preliminary design *** this study,an anisotropic soil model devel-oped by Norwegian Geotechnical Institute(NGI)based on the Active-Direct shear-Passive concept(NGI-ADP model)was adopted to conduct finite element(FE)analyses.A total of 682 cases were modeled to analyze the effects of five key parameters on twin-tunnel struc-tural forces;these parameters included twin-tunnel arrangements and subsurface soil properties:burial depth H,tunnel center-to-center distance D,soil strength s_(u)^(A),stiffness ratio G_(u)=s_(u)^(A),and degree of anisotropy ss_(u)^(P)=s_(u)^(A).The significant factors contributing to the bending moment and thrust force of the linings were the tunnel distance and overlying soil depth,*** degree of anisotropy of the surrounding soil was found to be extremely important in simulating the twin-tunnel construction,and severe design errors could be made if the soil anisotropy is ignored.A cutting-edge application of machine learning in the construction of twin tunnels is presented;multivariate adaptive regression splines and decision tree regressor methods are developed to predict the maximum bending moment within the first tunnel’s linings based on the constructed FE *** developed prediction model can enable engineers to estimate the structural response of twin tunnels more accurately in order to meet the specific target reliability indices of projects.

关键词： Twin tunnel Bending moment Thrust force Multivariate adaptive regression splines Decision tree regressor

Reliability Analysis of Slope Stability Considering Temporal Variations of Rock Mass Properties

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Computers, Materials & Continua 2020年第4期63卷 263-281页

作者： Xin Gu lin Wang Fuyong Chen hongrui li Wengang Zhang Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqingChina School of Civil Engineering Chongqing UniversityChongqingChina National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas Chongqing UniversityChongqingChina

Temporal variation of rock mass properties,especially the strength degradation due to drying-wetting cycles as well as the acidic wetting fluid(rainfall or reservoir water)is crucial to stability of reservoir rock *** on a series of drying-wetting cycling and experiments considering the influences of pH values,the degradation degree models of the reduced cohesion𝑐𝑐′,friction angle𝜑𝜑′are developed.2D stability analysis of the slope is subsequently carried out to calculate the factor of safety(Fs)via limit equilibrium method(LEM)and a predictive model of Fs is built using multivariate adaptive regression splines(MARS),revealing the effect of the drying-wetting cycles and pH *** reliability analysis by Monte Carlo simulation is performed to rationally consider the uncertainty and the temporal variation of the shear strength parameters of rock *** indicate that the MARS-based model can estimate the Fs *** Fs and the reliability indexβdecrease with increase of drying-wetting cycles,and the temporal variation of rock mass properties has significant influence on the slope *** the temporal variation of rock properties may overestimate the Fs and reliability indexβin the longer term.

关键词： Reservoir slope stability pH value reliability analysis temporal variation strength degradation

Probabilistic stability analysis of Bazimen landslide with monitored rainfall data and water level fluctuations in Three Gorges Reservoir, China

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Frontiers of Structural and Civil Engineering 2020年第5期14卷 1247-1261页

作者： Wengang ZHANG libin TANG hongrui li lin WANG Longfei CHENG Tingqiang ZHOU Xiang CHEN School of Civil Engineering Chongqing UniversityChongqing 400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing 400045China National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas Chongqing UniversityChongqing 400045China School of Civil Engineering Chongqing Three Gorges UniversityChongqing 404100China

Landslide is a common geological hazard in reservoir areas and may cause great damage to local residents’life and *** is widely accepted that rainfall and periodic variation of water level are the two main factors triggering reservoir *** this study,the Bazimen landslide located in the Three Gorges Reservoir(TGR)was back-analyzed as a case *** on the statistical features of the last 3-year monitored data and field instrumentations,the landslide susceptibility in an annual cycle and four representative periods was investigated via the deterministic and probabilistic analysis,*** results indicate that the fluctuation of the reservoir water level plays a pivotal role in inducing slope failures,for the minimum stability coefficient occurs at the rapid decline period of water *** probabilistic analysis results reveal that the initial sliding surface is the most important area influencing the occurrence of landslide,compared with other parts in the *** seepage calculations from probabilistic analysis imply that rainfall is a relatively inferior factor affecting slope *** study aims to provide preliminary guidance on risk management and early warning in the TGR area.

关键词： reliability analysis Bazimen landslide rainfall reservoir water level slope stability

转BtCry1Ac基因对107杨材性的非预期影响

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西部林业科学 2024年第1期53卷 82-87页

作者：李洪瑞赵志明张津门艳阔张子杨王进茂河北农业大学林学院河北保定071000 河北省洪崖山国有林场河北易县074200

为了探究外源BtCry1Ac基因对107杨材性性状产生的非预期影响,以转BtCry1Ac基因107杨2个株系(ECA1和ECA2)和野生型株系(WT)为材料,对其木材化学组分、物理和力学性质及纤维形态指标进行了定量测定。结果显示:BtCry1Ac基因的转入使107杨... 详细信息

为了探究外源BtCry1Ac基因对107杨材性性状产生的非预期影响,以转BtCry1Ac基因107杨2个株系(ECA1和ECA2)和野生型株系(WT)为材料,对其木材化学组分、物理和力学性质及纤维形态指标进行了定量测定。结果显示:BtCry1Ac基因的转入使107杨木材材性发生了非预期变化,具体表现为ECA1和ECA2的纤维素、灰分、苯醇抽出物及1%NaOH抽出物组分含量均显著低于WT(P<0.05);ECA1和ECA2的气干干缩性、全干干缩性显著低于WT(P<0.05),且ECA1和ECA2的气干密度、全干密度显著高于WT(P<0.05);ECA1和ECA2的冲击韧性、抗弯强度、抗弯弹性模量和顺纹抗压强度均显著高于WT(P<0.05);ECA1和ECA2的纤维长度显著低于WT(P<0.05)。总体表现为转基因株系的木材有着更小的干缩性,更高的密度和强度,其材性发生了非预期性改变,研究结果为转基因杨树的推广与应用提供了参考。

关键词： 107杨 BtCry1Ac基因木材材性纤维形态非预期效应

静-动荷载作用下欠固结软土盾构隧道长期沉降与最优埋深计算方法

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隧道建设（中英文） 2024年第9期44卷 1829-1840,I0005-I0016页

作者：仉文岗唐学成刘汉龙杨文钰刘智成王鲁琦李红蕊重庆大学土木工程学院重庆400045 山地城镇建设与新技术教育部重点实验室重庆400045 库区环境地质灾害国家地方联合研究中心重庆400045 广州地铁集团有限公司广东广州510220

为研究地表堆载、列车荷载和欠固结软土固结沉降联合作用下的盾构隧道长期沉降数值及其变化规律问题,依托广州市南沙至珠海(中山)城际项目,利用PLAXIS建立有限元模型计算外部作用下的盾构隧道长期沉降值,通过单因素敏感性分析和非线性... 详细信息

为研究地表堆载、列车荷载和欠固结软土固结沉降联合作用下的盾构隧道长期沉降数值及其变化规律问题,依托广州市南沙至珠海(中山)城际项目,利用PLAXIS建立有限元模型计算外部作用下的盾构隧道长期沉降值,通过单因素敏感性分析和非线性拟合方法分析各影响因子对长期沉降的影响并确定5种关键影响因子,提出长期沉降与最优埋深计算方法。研究结果表明:1)超固结比与隧道埋深对长期沉降影响最大,上部堆载荷载值、荷载作用宽度和列车荷载影响次之,而荷载距离、列车速度和渗透系数对长期沉降的影响可以忽略不计;2)为求解盾构隧道长期沉降值,提出静-动荷载作用下欠固结软土盾构隧道的长期沉降计算方法,计算值与模拟值吻合良好;3)将国家规范中盾构隧道变形控制值(20 mm)作为隧道沉降控制值,代入长期沉降计算公式,反推得到隧道最优埋深计算公式,其中软土欠固结特性对最优埋深影响最大。为有效控制长期沉降发展,建议将隧道整体置于较好的土层中,如需设置在淤泥及淤泥质土层中,则应进行地基处理、排水固结,以改善土体欠固结程度。

关键词：欠固结软土盾构隧道长期沉降非线性拟合上部堆载列车荷载

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The Weixi High-silica Granitoids in the Central Sanjiang Orogenic Belt,Southwest China:Implications for Growth of the Continental Crust

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Acta Geologica Sinica(English Edition) 2024年第3期98卷 641-656页

作者： WANG Qiuyu CHEN Shouming ZHANG hongrui li Saisai SinoProbe Laboratory Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China Guangxi Key Laboratory of Hidden Metallic Ore Deposit Exploration GuilinGuangxi 541004China

High-silica granitoids record the formation and evolution of the continental crust.A new intrusive complex has been recognized among silicic volcanic rocks of the Weixi arc,Southwest *** intrusions consist of granites,granitic porphyries,and *** U-Pb age data indicate that the Weixi granitoids formed at 248-240 Ma and were coeval with silicic volcanic rocks of the Weixi *** Weixi granitoids are enriched in Rb,Th,and U,depleted in Ba,Sr,Nb,Ta,and Ti,and have high light/heavy rare earth element ratios and slightly negative Eu *** Weixi granitoids have negative ε_(Nd)(t)values(-9.8 to-7.8)and negative zircon ε_(Hf)(t)values(-12.02 to-5.11).The geochemical and isotopic features suggest the Weixi granitoids were derived by partial melting of ancient crustal *** Weixi granitoids and silicic volcanic rocks were derived from the same magma by crystal accumulation and melt extraction,respectively,and they record the formation of a continental arc in the central Sanjiang orogenic belt.

关键词： granitoids geochemistry crystal accumulation continental crust Sanjiang orogen

氢化物原子荧光法测定红薯中硒含量的不确定度评定

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食品工业 2024年第7期45卷 292-296页

作者：李红蕊姜培苏珂杨念朱俊朋商丘市产品质量检验检测研究中心商丘476000 国家面粉及制品质量检验检测中心商丘476000

评定氢化物原子荧光法测定红薯中硒含量的不确定度。根据JJF 1059.1—2012和CNAS—GL006:2019,采用微波消解氢化物原子荧光法测定红薯中硒含量,建立数学模型,通过对整个试验过程产生的不确定度分析,计算合成不确定度和扩展不确定度。结... 详细信息

评定氢化物原子荧光法测定红薯中硒含量的不确定度。根据JJF 1059.1—2012和CNAS—GL006:2019,采用微波消解氢化物原子荧光法测定红薯中硒含量,建立数学模型,通过对整个试验过程产生的不确定度分析,计算合成不确定度和扩展不确定度。结果表明:红薯中硒的测定结果为0.162 0±0.006 9 mg/kg, k=2, p=95%;测量过程中不确定度主要来源为样品测量重复性、工作曲线拟合及方法回收率。试验对氢化物原子荧光法测定红薯中硒含量的过程和结果进行有效质量控制提供借鉴和参考。

关键词：红薯硒氢化物原子荧光法不确定度

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钠冷快堆关键热工水力问题研究现状及展望

原子能科学技术 2024年第9期58卷 1797-1816页

作者：杨红义薛秀丽周志伟林超李虹锐高鑫钊余新太马晓肖宇白罗锐中国原子能科学研究院北京102413 清华大学北京100084

钠冷快堆因其高热效率、高燃料利用率和固有安全性,以及能够实现闭式燃料循环以减少长寿命放射性废物的独特优势,被认为是第四代核能系统的首选堆型,也是目前国际核能领域的研究热点。本文概述了国际钠冷快堆及热工水力领域的发展历程... 详细信息

钠冷快堆因其高热效率、高燃料利用率和固有安全性,以及能够实现闭式燃料循环以减少长寿命放射性废物的独特优势,被认为是第四代核能系统的首选堆型,也是目前国际核能领域的研究热点。本文概述了国际钠冷快堆及热工水力领域的发展历程和未来方向,并指出了当前钠冷快堆热工水力领域发展所面临的主要问题。结合我国的发展现状和挑战,本文针对热工水力研究领域的三个关键核心方面进行了深入分析:冷却剂钠的流动换热特性、堆芯热工水力分析方法,以及自然循环余热排出的设计与验证。总结了国际范围内的研究成果,分析了遇到的技术挑战和未来研究的发展趋势,并探讨了我国在这些领域的研究现状及未来的研究方向。这些分析和总结旨在为中国钠冷快堆技术在提高安全性和经济性方面的技术挑战提供指导,同时也为未来钠冷快堆的热工水力设计和优化提供重要的参考依据,以推动我国钠冷快堆技术的进一步发展。

关键词：钠冷快堆热工水力自然循环盒间流固有安全非能动安全固有热工流体安全性湍流模型

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洁净钢精炼钙处理技术探析

山西冶金 2024年第6期47卷 70-73页

作者：魏鑫燕李宏锐刘政鹏张琦翟明磊青岛特殊钢铁有限公司炼钢厂山东青岛266409 青岛特殊钢铁有限公司研究院山东青岛266409 齐鲁工业大学继续教育学院山东济南250000 潍坊特钢集团有限公司山东潍坊261201

深入探讨了钙处理技术在洁净钢生产中的应用效果,并分析了目前存在的问题与潜在的解决方案。虽然钙处理有助于控制夹杂物形态,提升钢液可浇性,但过程中容易影响夹杂物的去除效率,增多大型夹杂物,甚至导致钢液二次氧化与耐火材料磨损。因... 详细信息

深入探讨了钙处理技术在洁净钢生产中的应用效果,并分析了目前存在的问题与潜在的解决方案。虽然钙处理有助于控制夹杂物形态,提升钢液可浇性,但过程中容易影响夹杂物的去除效率,增多大型夹杂物,甚至导致钢液二次氧化与耐火材料磨损。因此,对于无特殊夹杂物变性要求和可浇性问题,建议谨慎考虑是否进行钙处理。对于确实需要钙处理的情况,推荐在精炼结束后执行,并控制合适的添加量。结合工业实验和实践经验,提出了提升钢液洁净度的新策略,并建议以最低钙添加量为目标,确保钙处理技术的高效与洁净。研究结果不仅丰富了洁净钢精炼钙处理的理论基础,也为实际生产提供了可行的技术参考。

关键词：洁净钢钙处理技术夹杂物变性热力学数据精准控制