基于黏结单元力学参数随机赋值的压力隧洞衬砌水力劈裂分析
Hydraulic Fracturing Analysis of Pressure Tunnel Lining Based on Random Assignment of Mechanical Parameters of Cohesive Element
作者：陈国龙(浙江大学 建筑工程学院, 浙江 杭州 310058)；郜会彩(绍兴文理学院 土木工程学院, 浙江 绍兴 312000;浙江省岩石力学与地质灾害重点实验室, 浙江 绍兴 312000;浙江省山体地质灾害防治协同创新中心, 浙江 绍兴 312000)；胡云进(绍兴文理学院 土木工程学院, 浙江 绍兴 312000;浙江省岩石力学与地质灾害重点实验室, 浙江 绍兴 312000;浙江省山体地质灾害防治协同创新中心, 浙江 绍兴 312000)
Author：CHEN Guolong(College of Civil Eng. and Architecture, Zhejiang Univ., Hangzhou 310058, China)；GAO Huicai(School of Civil Eng., Shaoxing Univ., Shaoxing 312000, China;Key Lab. of Rock Mechanics and Geohazards of Zhejiang Province, Shaoxing 312000, China;Zhejiang Collaborative Innovation Center for Prevention and Control of Mountain Geologic Hazards, Shaoxing 312000, China)；HU Yunjin(School of Civil Eng., Shaoxing Univ., Shaoxing 312000, China;Key Lab. of Rock Mechanics and Geohazards of Zhejiang Province, Shaoxing 312000, China;Zhejiang Collaborative Innovation Center for Prevention and Control of Mountain Geologic Hazards, Shaoxing 312000, China)
收稿日期：2018-09-28 年卷（期）页码：2019,51(5):60-67
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：孔压黏结单元;压力隧洞;水力劈裂;Weibull分布;随机赋值;渗流-应力耦合
Key words：pore pressure cohesive element;pressure tunnel;hydraulic fracturing;weibull distribution;random assignment;hydro-mechanical coupling
基金项目：国家自然科学基金项目（51279177）；浙江省自然科学基金项目（LY18E090004）
中文摘要
压力隧洞衬砌水力开裂的随机性威胁深埋压力隧洞的安全运行。为准确模拟内水压作用下压力隧洞衬砌的随机水力劈裂过程，将混凝土衬砌视为两相介质，借助商业软件ABAQUS与MATLAB，结合用户材料子程序二次开发，基于黏结单元力学参数的随机赋值理论，建立压力隧洞衬砌内水外渗下的随机水力劈裂模型。首先，借助ABAQUS用户材料子程序二次开发，改进传统孔压黏结单元本构关系；利用改进的孔压黏结单元模拟衬砌中的初始缺陷等弱相，采用Weibull分布描述弱相力学参数的随机性；利用实体孔压单元模拟衬砌强相，强相材料参数取混凝土力学参数均值；内水压力按体力施加，建立压力隧洞衬砌渗流-应力-劈裂耦合分析模型；利用MATLAB对模型前处理与后处理。以某大型物理模型试验为例，采用本文模型进行压力隧洞衬砌的水力劈裂全过程模拟。结果表明：压力隧洞衬砌在高内水压下，不可避免发生开裂，出现内水外渗；衬砌裂缝分布稀疏，具有一定随机性；衬砌开裂部位钢筋应力先增长后回缩，与内水压力关系密切，内水外渗改善衬砌受力状况；提出的模型较好地模拟了压力隧洞衬砌在内水压作用下的随机水力劈裂特征、裂缝分布，且钢筋应力计算结果与模型试验实测结果吻合较好，为压力隧洞衬砌水力劈裂分析提供了一种可靠的方法。
英文摘要
The randomness of hydraulic fracturing on the lining of pressure tunnel threatens the safe operation of the deep buried pressure tunnel. In order to simulate the process of random hydraulic fracturing of the pressure tunnel lining with internal water pressure accurately, regarding concrete lining as two phase medium, using the commercial software ABAQUS and MATLAB, combined with the user material subroutine secondary development, a random hydraulic fracturing model was established with internal water exosmosis of the pressure tunnel lining based on the random assignment theory of mechanical parameters of the cohesive element. The priority task is to improve the constitutive relationship of traditional pore pressure cohesive element through the secondary development of ABAQUS user material subroutine, and the improved cohesive element was put forward to simulate the weak phase such as the initial default in the lining. Weibull distribution was recommended to describe the randomness of the mechanical parameters of the weak phase, while the strong phase of lining was simulated by solid pore pressure element, the mean value of mechanical parameters of the concrete was taken for the strong phase. The seepage-stress-fracturing coupling analysis model of pressure tunnel lining was proposed, which regards internal water pressure as body force. MATLAB was used for pre-processing and post-processing of the model. Taking a large-scale physical model test as an example, the whole process of hydraulic fracturing of the pressure tunnel lining was simulated using this model. The results showed that the lining of the pressure tunnel inevitably cracked and leaked out under high internal water pressure. The crack distribution of lining was sparse and random. The reinforcement stress of cracked lining increased first and then retract, which was closely related to the internal water pressure. Internal water exosmosis improved the stress condition of lining. The proposed model can well simulate the stochastic hydraulic fracturing characteristics of the pressure tunnel lining with internal water pressure well, and the calculation results of fracture distribution and reinforcement stress were in good agreement with the measured results of the model test. A reliable method for the hydraulic fracturing analysis of the pressure tunnel lining was provided.
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