基于有限差分法的江坪河溢洪洞出口段开挖方案对比研究

COMPARATIVE STUDY OF CONSTRUCTION METHOD OF JIANG PING RIVER SPILLWAY EXPORT BASED ON FINITE DIFFERENCE METHOD

基于项目组开发出的前处理程序,建立AUTOCAD初步建模、ANSYS进行形体切割和网格划分、FLAC3D进行模型计算的多软件联合建模模式,极大提高建模效率和精度.提出单位开挖方量对应的最大不平衡力λi的概念,结合数值模型关键点位移的检测技术和塑性区显示,针对两种开挖方案进行了对比分析.分析显示:不同开挖方案对最终位移的影响不明显,方案二的施工中的位移控制要稍优于方案一;演化过程对比说明,两方案第9步开挖的单位开挖方量对应的最大不平衡力λi比值最大,为最危险开挖步,方案二明显优于方案一,若采用方案一,第6步和第9步开挖时岩体所受开挖应力调整幅度增大,失稳可能性增大;最终塑性区为比较标准时两方案可行性相同.综合对比,方案二优于方案一.

A pre-treatment process based on the project team developed,joint multi-mode software moldelings,as AUTOCAD for preliminary modeling,ANSYS for physical cutting and meshing,FLAC3 D for model calculations.It greatly improved the efficiency and accuracy of the modelings.The concept of unbalanced force which corresponding to the largest excavation of unit amount side was Proposed.Combinating the detection technology and the plastic zone display of the key point numerical model displacement,the two programs of excavation were compared.The analysis was that different excavation programs had no significant effects on the final displacement,the construction program in the second displacement control programs were slightly better than one;The evolution contrast ofλ1shows that the unbalanced force ratio were the largest and also the most dangerous step,which corresponded to the excavation side of step 9of the two program units.It was obvious that the program two was better than that of one.Ifthe program one was opted,excavation of rock stress suffered by the adjustment would had increased and the possibility of instability would had increased when the Step 6and Step 9were excavating;The feasibility of the two programs were the same when the final plastic zone were on comparison standards.Comprehensive comparising,theprogram two is better than program one.