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Analyses of non-aqueous reactive polymer insulation layer in high geothermal tunnel

Journal of Rock Mechanics and Geotechnical Engineering 2023年第1期15卷 169-178页

作者： Yu Chen Shiyu Wang chengchao guo Cungang Lin Chenyang Zhao School of Civil Engineering Sun Yat-sen UniversityZhuhai519082China Southern Institute of Infrastructure Testing and Rehabilitation Technology Huizhou516000China

The scenario of geothermal tunnel is commonly observed around the world,and increases with the new constructions in the long and deep tunnels,for example in *** insulation is generally divided into active and passive *** passive insulation,it is an effective way to set low thermal con-ductivity materials as the thermal insulation layer as the choice of insulation material mainly depends on the thermal *** is a kind of material with good geothermal performance,but there are relatively few *** this context,the transient plane source(TPS)method was used to measure the thermal conductivity of the developed ***,the temperature field of the high geothermal tunnel insulated by the non-aqueous reactive polymer layer was *** the parametric analysis results,the suggestions for the tunnel layers were proposed *** revealed that the thermal conductivity of polymer first increases and then decreases with *** are two rising sec-tions(?40e10?C and 20e90?C),one flat section(10e20?C)and one descending section(>90?C).It is observed the thermal conductivity of polymer increases with increase of the density of insulation layer and the density,and the thermal conductivity decreases when exposed to high *** temperature of the surrounding rocks increases with increase of the thermal conductivity and the thickness of ***,a more economical thickness(5 cm)was *** on the parametric study,a thermal insulation layer with thermal conductivity less than 0.045 W/(m K),thickness of 5 cm and a density less than 0.12 g/cm 3 is suggested for practice.

关键词： Geothermal tunnel Non-aqueous reactive polymer Thermal conductivity Heat insulation

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The role of polyurethane foam compressible layer in the mechanical behaviour of multi-layer yielding supports for deep soft rock tunnels

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第11期16卷 4554-4569页

作者： Haibo Wang Fuming Wang chengchao guo Lei Qin Jun Liu Tongming Qu School of Civil Engineering Sun Yat-sen UniversityGuangzhou510275China Southern Marine Science and Engineering Guangdong Laboratory Zhuhai519000China Guangdong Key Laboratory of Oceanic Civil Engineering Zhuhai519082China Guangdong Research Center for Underground Space Exploitation Technology Guangzhou510275China Southern Institute of Infrastructure Testing and Rehabilitation Technology Huizhou516029China Department of Hydraulic Engineering School of Infrastructure EngineeringDalian University of TechnologyDalian116024China Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyClearwater BayKowloonHong KongChina

The polyurethane foam(PU)compressible layer is a viable solution to the problem of damage to the secondary lining in squeezing ***,the mechanical behaviour of the multi-layer yielding supports has not been thoroughly *** fill this gap,large-scale model tests were conducted in this *** synergistic load-bearing mechanics were analyzed using the convergenceconfinement *** types of multi-layer yielding supports with different thicknesses(2.5 cm,3.75 cm and 5 cm)of PU compressible layers were investigated *** image correlation(DIC)analysis and acoustic emission(AE)techniques were used for detecting the deformation fields and damage evolution of the multi-layer yielding supports in *** indicated that the loaddisplacement relationship of the multi-layer yielding supports could be divided into the crack initiation,crack propagation,strain-hardening,and failure *** with those of the stiff support,the toughness,deformability and ultimate load of the yielding supports were increased by an average of 225%,61%and 32%,***,the PU compressible layer is positioned between two primary linings to allow the yielding support to have greater mechanical *** analysis of the synergistic bearing effect suggested that the thickness of PU compressible layer and its location significantly affect the mechanical properties of the yielding *** use of yielding supports with a compressible layer positioned between the primary and secondary linings is recommended to mitigate the effects of high geo-stress in squeezing tunnels.

关键词： Multi-layer yielding supports Polyurethane foam compressible layer Synergistic mechanism Large-scale model test Deep soft rock tunnels

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Evaluation and attribution of trends in compound dry-hot events for major river basins in China

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Science China Earth Sciences 2024年第1期67卷 79-91页

作者： Shaotang XIONG Tongtiegang ZHAO chengchao guo Yu TIAN Fang YANG Wenlong CHEN Xiaohong CHEN Key Laboratory of Water Security Guarantee in Guangdong-Hong Kong-Marco Greater Bay Area of Ministry of Water Resources&Sun Yatsen University/Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Guangzhou 510275China China Institute of Water Resource and Hydropower Research Beijing 100038China Pearl River Hydraulic Research Institute Guangzhou 510611China

Concurrent compound dry and hot events(CDHEs)amplified more damange on the ecosystems and human society than individual *** climate change,compound dry and hot events become more frequent on a global *** paper proposes a mathematical method to quantitatively attribute changes of CDHEs to changes of precipitation,change in temperature and change in the dependence between precipitation and *** attribution is achieved by formulating the total differential equation of the return period of CDHEs among Meta-gaussian model.A case study of China is devised based on monthly precipitation and temperature data during the period from 1921 to 2020 for 80 major river *** is found that temperature is the main driving factor of increases in CDHEs for 49 major river basins in China,except for the upper and middle reaches of the Yangtze *** West China,precipitation changes drove the increase in CDHEs in 18 river basins(23%),particularly in parts of North Xinjiang,Qinghai and *** the other hand,dependence between precipitation and temperature dominated changes of CDHEs in 13 river basins(16%)of China with other factors,including parts of South China,East China and Northwestern ***,changes in both the mean and spread of precipitation and temperature can also contribute to changes in CDHEs.

关键词： Climate extreme Compound dry and hot extreme Precipitation Temperature Return period

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Responses of calcareous sand foundations to variations of groundwater table and applied loads

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第4期14卷 1266-1279页

作者： Dingfeng Cao Sanjay Kumar Shukla Linqing Yang chengchao guo Jinghong Wu Fuming Wang School of Civil Engineering Sun Yat-sen UniversityGuangzhou510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519082China Discipline of Civil and Environmental Engineering School of EngineeringEdith Cowan UniversityPerth6027Australia School of Architectural Engineering Guangzhou Institute of Science and TechnologyGuangzhou510540China School of Civil Engineering Suzhou University of Science and TechnologySuzhou215011China

The long-term settlement of calcareous sand foundations caused by daily periodic fluctuations has become a significant geological hazard,but effective monitoring tools to capture the deformation profiles are still rarely *** this study,a laboratory model test and an in situ monitoring test were *** optical frequency domain reflectometer(OFDR)with high spatial resolution(1 mm)and high accuracy(10-6)was used to record the soil strain responses to groundwater table and varied *** results indicated that the fiber-optic measurements can accurately locate the swelling and compressive *** the loading process,the interlock between calcareous sand particles was detected,which increased the internal friction angle of *** foundation deformation above the sliding surface was dominated by compression,and the soil was continuously compressed beneath the sliding *** 26e48 h,calcareous sand swelling occurred gradually above the water table,which was primarily dependent on capillary *** swelling of the soil beneath the groundwater table was completed rapidly within less than 2 *** the groundwater table and load remain constant,the compression creep behavior can be described by the Yasong-Wang model with R2¼*** daily periodically varying in situ deformation of calcareous sand primarily occurs between the highest and lowest groundwater tables,i.e.4.2e6.2 m *** tuff interlayers with poor water absorption capacity do not swell or compress,but they produce compressive strain under the influence of deformed calcareous sand layers.

关键词： Distributed fiber optic sensing(DFOS) Calcareous sand Optical fiber Optical frequency domain reflectometer (OFDR) Soil foundation settlement

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Model test and numerical simulation of a new prefabricated double-row piles retaining system in silty clay ground

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Underground Space 2023年第6期13卷 262-280页

作者： Ruisong Wang Hao Yang Pengpeng Ni Chenyang Zhao chengchao guo Huihuan Ma Pu Dong Huqing Liang Mengxiong Tang School of Civil Engineering Sun Yat-sen UniversitySouthern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Guangdong Key Laboratory of Oceanic Civil EngineeringGuangdong Research Center for Underground Space Exploitation TechnologyZhuhai 519082China Beijing Urban Rail Transit Construction Engineering Co. LtdBeijing 100088China BeSTDR Infrastucture Hospital Zhumadian 463400China School of Architecture and Civil Engineering Huizhou UniversityHuizhou 516008China Guangzhou Municipal Construction Group Co. LtdGuangzhou 510275China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

This paper introduces a new prefabricated recyclable double-row piles retaining system for excavations in silty clay *** model test and numerical simulation are conducted to study the system behavior upon *** horizontal displacement(δ_(h)),Von Mises stress(δ_(M)),strain(ε),ground surface settlement(δ_(v)),and earth pressure are systematically ***,the monitoring data of 13 excavation cases supported by double-row piles retaining system are presented and *** experimental results can basically match the numerical results,and the maximumδ_(M),maximum bending moment(M_(max)),maximum horizontal displacement(δ_(hm))of structural members are all less than the tolerance *** ground surface settlement model of double-row piles retaining system consists of three zones,i.e.,rebound influence zone,primary influence zone and secondary influence *** dhm values are 0.07%–1.42%of the excavation depth(He).The maximum ground surface settlement(δ_(vm))is generally less than *** ratio ofδ_(vm)=δ_(hm)varies between 0.09 and 0.76,with an average value of *** observed earth pressure on the retained side of front pile(paf)is about 0.53–0.57γH below the excavation *** the excavation surface,p_(af)decreases dramatically when getting closer to the ground surface.

关键词： Prefabricated recyclable structure Double-row piles retaining system Physical model test Numerical simulation Deformation

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Study on Ground-Penetrating Radar (GPR) Application in Pavement Deep Distress Detection

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Journal of Transportation Technologies 2019年第2期9卷 232-259页

作者： Songtao Li chengchao guo College of Water Conservancy and Environment Zhengzhou University Zhengzhou China Industrial Technology Research Institute Chongqing University Chongqing China School of Civil Engineering Sun Yat-sen University Guangzhou China

As some deep distresses exist in pavement structures, ground-penetrating radar (GPR) reflected waves will vary at interfaces and defects. Aimed at detecting the distresses in terms of position, severity and degree, electromagnetic forward simulations based on 400 MHz and 900 MHz antennas were conducted respectively. The dielectric models concerning homogeneous or coupling distresses of pavements were established, and the effects of various distresses on detection were analyzed through reflected wave images. Relying on GPR tests and field tests, coring and excavation data acquired before rehabilitation were compared and verified. The calculation results match the field measurement results. Thus, the detection method based on GPR was proposed for pavement deep distresses.

关键词： Pavement Deep Distress GPR Electromagnetic Forward Simulation Dielectric Model Detection

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一种采用U型配筋新型复合保温墙板节点地震损伤模型研究

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振动与冲击 2023年第12期42卷 290-298页

作者：马少春谷宇鲍鹏郭成超河南大学土木建筑学院开封市工程修复与材料循环工程技术研究中心河南开封475004 郑州大学黄河实验室郑州450001

为了探究结构与保温一体化新型复合墙板节点的抗震性能及地震损伤模型,提出了一种采用U型节点配筋形式的新型复合保温墙板节点。设计并制作了6个试验样本。通过工作性能力学试验,研究了该类墙板节点试件的破坏机理、滞回性能、承载能力... 详细信息

为了探究结构与保温一体化新型复合墙板节点的抗震性能及地震损伤模型,提出了一种采用U型节点配筋形式的新型复合保温墙板节点。设计并制作了6个试验样本。通过工作性能力学试验,研究了该类墙板节点试件的破坏机理、滞回性能、承载能力以及延性系数等指标。另外,通过研究发现,常用的Park损伤模型并不能较好地反映试件损伤发展情况。因此,为了能准确描述新型复合保温墙板节点的地震损伤发展,该文章在试验的基础上提出了一类适用于该类试件的改进地震损伤模型。通过实例验证发现,反映出可以利用较多指标对损伤的合理评价,应用前景具有广泛性。

关键词：损伤模型墙板节点陶粒混凝土抗震试验滞回及骨架曲线

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非均布移动荷载下含表面裂缝路面结构应力响应

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公路交通科技 2011年第8期28卷 19-24页

作者：王鹏郭成超郑州大学水利与环境学院河南郑州450002

采用移动加载的动载模型,考虑轮胎花纹形式,选用非均布轮胎荷载模式,建立三维有限元路面结构模型分析了非均布移动荷载作用下含表面纵向和横向裂缝路面结构的应力响应,以探求移动荷载作用下表面裂缝的开裂机理。采用空间有限元——时间... 详细信息

采用移动加载的动载模型,考虑轮胎花纹形式,选用非均布轮胎荷载模式,建立三维有限元路面结构模型分析了非均布移动荷载作用下含表面纵向和横向裂缝路面结构的应力响应,以探求移动荷载作用下表面裂缝的开裂机理。采用空间有限元——时间差分法对问题进行数值求解。分析过程中对裂缝尖端网格局部进行加密处理,并用位移法求取裂缝尖端的应力强度因子。分析得出随着荷载的移动,处于荷载正下方点位的裂缝Ⅰ型应力强度因子最大。移动荷载作用正下方纵缝的Ⅰ型应力强度因子的值均比静载时大,移动荷载可加速裂缝的开展。对于横缝随着荷载距离裂缝越近,对裂缝的影响越大。移动车辆荷载对纵向裂缝的影响比横缝更大。因此要特别注意路面表面纵向裂缝的预防和养护。

关键词：道路工程路面结构有限元分析移动荷载表面裂缝养护

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装配式L形截面夹芯组合剪力墙节点抗震性能试验

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土木工程学报 2022年第S1期55卷 49-55页

作者：马少春赵亚坤郭成超鲍鹏河南大学开封市工程修复与材料循环工程技术研究中心河南开封475004 郑州大学河南郑州450001

为研究装配式L形截面夹芯组合剪力墙节点的整体工作性能,设计了由环形水平钢筋连接试件及水平贯通钢筋连接试件共两类。详细考察了试件的工作状态、破坏机理、滞回性能、刚度退化及耗能等变化规律,并对其延性性能进行了评价。结果表明:... 详细信息

为研究装配式L形截面夹芯组合剪力墙节点的整体工作性能,设计了由环形水平钢筋连接试件及水平贯通钢筋连接试件共两类。详细考察了试件的工作状态、破坏机理、滞回性能、刚度退化及耗能等变化规律,并对其延性性能进行了评价。结果表明:试件发生了典型的弯剪破坏,主要集中在腹板脚部混凝土被拉裂或压碎、钢筋拉长或压弯。通过对比分析发现,环形水平钢筋连接试件的开裂、屈服、峰值荷载及相应的变形均得到大幅度的提高;通过对耗能性能进行评估,得出的结论一致等。说明环形钢筋可以有效增强腹板与暗柱、翼缘与暗柱之间的连接,有助于综合提高试件的抗震能力。

关键词：夹芯剪力墙节点抗震试验装配式滞回及骨架曲线刚度

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便携式弯沉仪快速检测路基压实度的应用研究

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路基工程 2008年第6期 131-132页

作者：郭成超王鹏郑州大学环境与水利学院河南郑州450002

通过对素土、水泥稳定土和二灰土典型路基填料的压实度与PFWD检测弯沉、模量关系的分析,表明可用PFWD快速评价路基的压实质量。

关键词：压实度 PFWD 弯沉模量

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