严寒强震区特高拱坝筑坝关键技术难题及应对措施

以分析严寒、强震区修建特高拱坝的关键技术为目标,针对QBT工程特高拱坝建基面选择、坝体应力控制及动力反应分析、坝肩变形稳定、坝体开裂控制、大坝整体抗灾能力等关键技术问题,采取了体形裕度设计、智能温控、综合抗震控制等应对措施。结果显示,多目标优取的拱坝体形,具有适应性强、抗震性能好、安全度充足、整体安全性高等特点。结果表明,结合智能温控措施,低热水泥及坝体全断面保温的采用可有效地降低温度应力,控制裂缝的产生,解决严寒地区工程工期短、浇筑量大、温控与浇筑强度需协调一致等系列控制工期的施工矛盾,保障建设期及运行期的工程安全运行。综合抗震措施的采用使坝体在设计地震作用下,整体性好,满足抗震设计要求。研究成果为今后在严寒强震区筑坝提供了更多有益的参考。

Key technologies and countermeasures for construction of super-high arch dam in severe cold and strong seismic region

By taking the key technologies for construction of super-high arch dam in severe cold and strong seismic region as the objective，the countermeasures，such as the shape margin design，dam body cracking control，integrated seismic control，etc.，are adopted for the key technologies of the selection of foundation face，dam stress control and dynamic response analysis，stabilization of abutment deformation，dam body cracking control，integral anti-disaster ability of dam，etc. for the construction of QBT Project. The result shows that the shape of the arch dam from the multi-objective optimization has the characteristics of strong adaptability，better seismic performance，sufficient safety，high integral safety. It is indicated from the result that combined with in the intelligent temperature control measure，the adoptions of low thermal cement and full-sectional insulation of dam body can effectively decrease the temperature stress for controlling the occurrence of crack and solving a series of the construction contradictions for control of the construction period within severe-cold region，i.e. short time limit for construction，large volume of concrete placement，coordination between temperature control and concrete placing strength，etc.，thus ensuring the safe operation of the project during both the construction and the operation periods. The adoption of the integrated seismic measure makes a better integrity for the dam body under the effect of the design earthquake，which can meet the relevant requirement of the seismic design. The study result can provide more beneficial references for the dam construction in severe-cold and strong seismic region in the days to come.