非连续变形分析方法(DDA)剪切机制研究  

Investigating shear mechanics of discontinuous deformation analysis

作　　者：龚文俊[1,2,3] 王运生[3] 罗永红[3] GONG Wen-jun WANG Yun-sheng LUO Yong-hong(Department of Civil Engineering, Beihang University, Beijing 100083, China Department of Geotechnical Engineering, China Institute of Water Resources and Hydropower, Beijing 100048, China State Key laboratory of Geohazard Prevention and Geoenvironmental Protection, Chengdu University of Technology, Chengdu 610059, China)

机构地区：[1]北京航空航天大学土木工程系,北京100083 [2]中国水利水电科学研究院岩土工程研究所,北京00048 [3]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059

出　　处：《岩土工程学报》2016年第11期2059-2068,共10页Chinese Journal of Geotechnical Engineering

基　　金：地质灾害防治与地质环境保护国家重点实验室开放基金项目(成都理工大学)(SKLGP2014K012)

摘　　要：以倾斜板上的块体稳定对象,针对摩擦性材料,对DDA剪切机制开展了研究工作。研究结果表明,即使当接触面摩擦强度略大于临界摩擦角criT?时,在一个边边接触中常会出现锁定与滑动两种不同的状态。在后续计算过程中,由于这种状态会受到阻止,会有不合理的能量产生。这种能量有可能会导致块体难以稳定。DDA可以需要选择适当的接触刚度来控制这种能量的量级,并最终使块体理论临界摩擦角criT?附近稳定。进一步研究表明,出现这一结果主要是由于单独对边边接触上的两个角边接触进行抗剪分析。基于此,提出一种新的改进方法,将边边接触中的两个角边接触进行共剪分析,即将两个角边接触上的剪切力之和与摩擦阻力之和进行分析。测试结果表明,该方法不会受到罚弹簧值和块体弹模的影响。所分析的临界摩擦角与理论值非常接近。Using a classical case, a block on an incline, shear mechanics of discontinuous deformation analysis（DDA） for frictional interface is especially investigated. The results reveal that two contact states are commonly emerged in one edge-to-edge contact, even when the frictional angel is slightly above the theoretical critical friction angle φTcri. Owing to that the state of the block will be prevented in the following processes, unreasonable energy will be inevitably produced, which will also make the block hard to get steady. When the Young＇s modulus of the block is fixed, carefully selecting a penalty value is required for DDA to stabilize the block when the friction angle is slightly above φTcri. A further investigation reveals the main cause is that individually analyzing the two vertex-to-edge contacts in one edge-to-edge contact. Instead individually analyzing the two contacts in one edge-to-edge contact, this study introduces an edge-to-edge treatment to overcome the deficiency of the original DDA. The test results indicate that the new improved DDA can handle well shear problems with high accuracy, and the penalty value and Young＇s modulus of the block have little influence on its accuracy.

关 键 词：DDA 临界摩擦角 罚弹簧 共剪分析 

分 类 号：TU43[建筑科学—岩土工程]