基于荷载结构法和强度折减法的人防工程安全性评估方法  

A method for evaluating safety of civil air defense structure based on load structure method and strength reduction method

作　　者：曹嘉祺 王洪新 王平 孙德安[1] CAO Jia-qi;WANG Hong-xin;WANG Ping;SUN De-an(School of Mechanics and Engineering Science,Shanghai University,Shanghai 200444,China;Shanghai Urban Construction Municipal Engineering(Group)Co.Ltd.,Shanghai 200065,China)

机构地区：[1]上海大学力学与工程科学学院,上海200444 [2]上海城建市政工程(集团)有限公司,上海200065

出　　处：《岩土力学》2023年第7期2105-2114,共10页Rock and Soil Mechanics

摘　　要：科学有效地对既有人防工程结构进行安全评估,已成为保证城市地下安全的关键。为了克服现有安全评估方法的不足,提出了基于荷载结构法和强度折减法的安全评估方法。利用荷载结构法,将土体对人防工程衬砌的作用转化为荷载以及地基弹簧作用,采用混凝土损伤塑性模型模拟衬砌结构损伤情况,通过荷载增大法和刚度折减法得到衬砌的安全系数值K1;采用强度折减法对土体-衬砌进行有限元建模分析,得到结构或围岩土体破坏时的安全系数值K2。结构的整体安全系数K为两者的较小值。利用上述方法分析了裂缝工况、水位变化等不同因素对结构安全系数的影响。结果表明:荷载结构法和强度折减法均可用于人防工程结构的安全评估;结构的安全系数主要受裂缝和水位的影响,裂缝越深,对结构的安全越不利,安全等级越低;当地下水位高于结构底部且内部渗水时,水位越高,结构越安全;结构内部不渗水时,水位越高,结构安全系数越小。人防工程结构安全的定量评估有利于工程后续处置,研究成果为地下结构安全评估提供了新途径。Scientific and effective safety assessment of existing civil air defense structures has become a key issue to ensure urban underground safety.In order to overcome the shortcomings of the existing safety evaluation methods,a safety evaluation method based on load structure method and strength reduction method is proposed.First,the load structure method is used to convert the impact of surrounding soils on the tunnel lining into load and foundation spring.The concrete damage plastic(CDP)model is used to simulate the damage of lining structure,and the value of safety factor(K1)of lining is obtained by load increasing method and stiffness reduction method.Meanwhile,the finite element modeling analysis of soil lining is carried out by using the strength reduction method,and the safety factor value(K2)of the structure or soil mass at failure is obtained.The overall safety factor(K)of the structure is the smaller value of both.Finally,the influence of different factors such as crack condition and water level change on the structural safety factor is analyzed by using the above methods.The results show that the load structure method and strength reduction method can be used for evaluating the safety of civil air defense structures.The safety factor of the structure is mainly affected by cracks and water level.The deeper the crack is,the more unfavorable it is to the structure,and the lower the safety level of the structure is.When the underground water level is above the structure bottom and there is water seepage inside the structure,the higher the water level is,the safer the structure is.When there is no water seepage inside the structure,the higher the water level is,the lower the safety factor of the structure is.The quantitative evaluation of structures is conducive to the subsequent disposal,and the research results provide a new way for the safety assessment of underground structures.

关 键 词：人防工程 安全评估 荷载结构法 强度折减法 

分 类 号：TU929[建筑科学—建筑设计及理论]