A modified discontinuous deformation analysis (DDA) algorithm was proposed to simulate the failure behavior of jointed rock. In the proposed algorithm, by using the Monte-Carlo technique, random joint network was gene...A modified discontinuous deformation analysis (DDA) algorithm was proposed to simulate the failure behavior of jointed rock. In the proposed algorithm, by using the Monte-Carlo technique, random joint network was generated in the domain of interest. Based on the joint network, the triangular DDA block system was automatically generated by adopting the advanced front method. In the process of generating blocks, numerous artificial joints came into being, and once the stress states at some artificial joints satisfy the failure criterion given beforehand, artificial joints will turn into real joints. In this way, the whole fragmentation process of rock mass can be replicated. The algorithm logic was described in detail, and several numerical examples were carried out to obtain some insight into the failure behavior of rock mass containing random joints. From the numerical results, it can be found that the crack initiates from the crack tip, the growth direction of the crack depends upon the loading and constraint conditions, and the proposed method can reproduce some complicated phenomena in the whole process of rock failure.展开更多
目的评价早期预防脑瘫患儿继发髋关节发育不良疗法的有效性。方法检索CNKI、万方、VIP、CBM、PubMed、Embase、Web of Science和Cochrane Library数据库,收集从建库至2022年4月发表的有关预防脑瘫髋关节发育异常疗法的RCT。由两位评价...目的评价早期预防脑瘫患儿继发髋关节发育不良疗法的有效性。方法检索CNKI、万方、VIP、CBM、PubMed、Embase、Web of Science和Cochrane Library数据库,收集从建库至2022年4月发表的有关预防脑瘫髋关节发育异常疗法的RCT。由两位评价员独立筛选文献、提取资料并评价纳入研究的偏倚风险后,采用Stata 16.0软件和ADDIS 1.16.8软件进行贝叶斯网状Meta分析。结果最终纳入21个RCT,共包括1228例脑瘫患儿。网状Meta分析表明:(1)常规康复治疗联合家庭髋关节姿势管理、肌肉电刺激、穴位埋线、WBV,分别在改善MP值、内收肌肌张力、GMFM-E区评分、髋关节ROM评价方面疗效最佳;(2)在改善腘绳肌肌张力的评价中,常规康复治疗+靳三针头针+体针治疗效果明显优于常规康复治疗。结论家庭髋关节姿势管理在改善MP值方面临床前景最好,针灸联合常规康复治疗在改善肌张力方面疗效明确。展开更多
基金Projects(50479071, 40672191) supported by the National Natural Science Foundation of ChinaProject(SKLZ0801) supported by the Independent Research Key Project of State Key Laboratory of Geomechanics and Geotechnical EngineeringProject(SKLQ001) supported by the Independent Research Frontier Exploring Project of State Key Laboratory of Geomechanics and Geotechnical Engineering
文摘A modified discontinuous deformation analysis (DDA) algorithm was proposed to simulate the failure behavior of jointed rock. In the proposed algorithm, by using the Monte-Carlo technique, random joint network was generated in the domain of interest. Based on the joint network, the triangular DDA block system was automatically generated by adopting the advanced front method. In the process of generating blocks, numerous artificial joints came into being, and once the stress states at some artificial joints satisfy the failure criterion given beforehand, artificial joints will turn into real joints. In this way, the whole fragmentation process of rock mass can be replicated. The algorithm logic was described in detail, and several numerical examples were carried out to obtain some insight into the failure behavior of rock mass containing random joints. From the numerical results, it can be found that the crack initiates from the crack tip, the growth direction of the crack depends upon the loading and constraint conditions, and the proposed method can reproduce some complicated phenomena in the whole process of rock failure.
