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滇中引水工程隧洞衬砌施工期温控措施

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隧洞衬砌混凝土属于典型的薄壁大体积混凝土,衬砌采用泵送混凝土、水化温升高,围岩约束大,衬砌易产生温度裂缝.为探究合理的隧洞衬砌施工期温控措施,采用三维有限元软件,考虑围岩和衬砌接触,开展了滇中引水工程某隧洞混凝土典型衬砌段施工期的温度场和温度应力场分布规律分析.结合现场监测数据,反馈分析了衬砌段表面保温系数为16.7 kJ/(m2·h·℃).研究了不同的浇筑温度、浇筑段长度、浇筑季节、混凝土自生体积变形特性对混凝土衬砌温度应力场的影响.结果显示:浇筑温度越高温度应力越大,浇筑温度每升高4℃,最小抗裂安全度降低0.30;高温季节浇筑最大应力较大,甚至>3.5 MPa;衬砌结构应采用合适的分段长度;采用微膨胀混凝土有利于抗裂.研究成果可为滇中引水工程隧洞衬砌混凝土温控施工提供参考.
Temperature Control Measures during Construction Period for the Tunnel Lining of Central Yunnan Water Diversion Project
Tunnel lining concrete is a typical example of thin-walled,large-volume concrete.During construction,the high hydration temperature of pumped concrete and the significant constraints imposed by the surrounding rock often lead to temperature-induced cracking.To explore reasonable temperature control measures,we employed three-dimensional finite element software to analyze the temperature field and thermal stress distribution in a typical tunnel lining section of the Central Yunnan Water Diversion Project.Contact elements were used to model the inter-actions between the surrounding rock and the lining.Based on on-site monitoring data,we performed a feedback a-nalysis on the surface insulation coefficient of the lining section,which was 16.7 kJ/(m2·h·℃).We investiga-ted how different pouring temperatures,section lengths,seasons,and the autogenous volumetric deformation of con-crete affect the thermal stress field of the concrete lining.Our findings indicate that higher pouring temperatures in-crease thermal stress;specifically,a 4℃ rise in pouring temperature reduces the minimum anti-cracking safety fac-tor by 0.30.The maximum stress exceeded 3.5 MPa when concrete was poured during high-temperature seasons.Appropriate segment lengths for the lining structure and micro-expansion concrete can enhance crack resistance.The findings offer valuable insights for temperature control in tunnel lining concrete for the Central Yunnan Water Diversion Project.

tunnel lining3D finite element analysistemperature stress fieldtemperature control measurescracking riskCentral Yunnan Water Diversion Project

杨蒙、覃茜、杨旭、王樱、徐航

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云南省滇中引水工程有限公司,昆明 650205

云南省滇中引水工程建设管理局,昆明 650205

长江科学院材料与结构研究所,武汉 430010

水利部水工程安全和病害防治工程技术研究中心,武汉 430010

云南省曲靖市富源县水务局,云南富源 655599

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隧洞衬砌 三维有限元 温度应力场 温控措施 抗裂风险 滇中引水工程

云南省重大科技专项计划项目云南省重大科技专项计划项目国家自然科学基金项目武汉市自然科学基金项目

202102AF080001202002AF080003520090112023020201020360

2024

长江科学院院报
长江科学院

长江科学院院报

CSTPCD北大核心
影响因子:0.618
ISSN:1001-5485
年,卷(期):2024.41(10)