田湾核电5-8号机组第一阶段取水明渠工程北导流堤抗震稳定分析

Seismic Stability Analysis of Breakwater of Water Intake Engineering for Nuclear Power Plant

以田湾核电5-8号机组第一阶段取水明渠工程北导流堤实际工程为背景,详细阐述了核电规范规定的3种稳定性分析方法,即滑动面法、静力有限元法和动力有限元法。运用Geo-slope软件分析导流堤抗震稳定性,计算出在不同地震动SL1和SL2条件下滑动面位置和最小安全系数。SL1条件下安全系数大于1;对SL2条件下安全系数小于1,导流堤发生瞬时失稳的情况,进行了Newmark滑移量分析,但由于非线性地基土液化区的存在,需进一步应用有效应力动力分析方法进行补充分析,结果表明:SL1地震动作用下,导流堤稳定性良好;SL2地震动作用下虽发生瞬时失稳,但变形量很小,仍然具有安全性。计算方法和分析成果对类似核电导流堤抗震稳定分析具有一定的指导和借鉴作用。

Sliding surface method, static finite element method and dynamic finite element method from nuclear power standard are introduced in detail. By using the geotechnical engineering soft- ware Geo-slope we make a seismic stability analysis of diversion dike, which is based on north di- version dike of water intake channel for Tianwan nuclear power unit 5-8, with these three kinds of methods we obtain the safety coefficient and the location of the sliding surface under the effects of ground motion SL-1 and ground motion SL-2. The safety coefficient is greater than 1 for SL1, in view of the situation that the safety coefficient is less than 1 and transient instability of diver- sion dike happens, Newmark slip analysis is carried out. Further more, applying dynamic effec- tive stress analysis method to overcome the shortage of Newmark slip analysis due to the exist- ence of liquefaction and in order to get the permanent deformation of the diversion dike. The re- suits show that under the ground motion SL1, the overall stability of diversion dike is great; Al- though the transient instability occurs under SL2, it doesn＇t affect the normal use of nuclear power equipment because of the small deformation. The calculation method and the analysis re- sults have certain guidance and reference for seismic stability analysis of some other similar diver- sion dike structure of nuclear power plant.