日本岩土工程极限状态设计法进展

State-of-art of Geotechnical Engineering Limit State Design Methods in Japan

日本目前正处在由规格规定型设计(日文:仕样规定)向性能规定型设计的转轨阶段。第一层次规范《土木·建筑设计基本规定》为岩土工程极限状态设计的引领性规范;第三层次的《岩土工程总设计规程》(简称Geo-Code 21)给出了性能设计的原则、性能矩阵、校核方法和土工参数确定的方法;第四层次的公路、港口、河川、铁路等行业规范在2010年前后陆续出版实施,引入了性能要求,安全、使用和修复极限状态等理念,但在具体的工程设计中,仍然采用容许应力法进行安全设计计算。随着极限状态设计法的导入,将会出现设计风险问题,新的技术层面的、社会制度层面的诸多问题尚待进一步深入研究。

Geotechnical engineering design methods in Japan are developing from specification design to per- formance based design. The level 1 code, Basis of Structural Design for Buildings and Public Works, is a leading code for geotechnical engineering limit state design. The level 3 code, a Comprehensive Design Code in Geotechnical Engineering and Foundation Field （Geo-code 21）, specifies the principals, perform- ance matrix, verification approaches and determination method of design parameters. The level 4 codes, such as the codes for highway, railway, harbor, river engineering, were published around 2010. Concepts of performance requirement, safety limit state, serviceability limit state and restorability limit state were introduced. However, allowable stress method is still used to check the ultimate stability for geotechnical structures in these codes. With the changing of the limit state design method, new technical problems and society system problems should be studied and solved in the future for prevention of the design risks.