首都圈地区震源机制解综合研究

Comprehensive statistical analysis was performed on the basic features of focal mechanisms of 619 ML≥2.0 earthquakes which occurred in the capital circle area from January 2002 to June 2010. By dividing the capital area into three studying regions based on regional tectonic characteristics, cluster analysis was conducted on the focal mechanisms of all subregions using the longest distance method in the statistical cluster analysis to study the characteristics of tectonic stress tensors. The result shows that dominant P-axis azimuth distribution is NNE-NEE and that of T-axis is NNW--NWW, most of the focal areas are controlled by a horizontal stress field and rupture is mainly of horizontal strike-slip. The maximum principal compression stress orientation is NE75° in the west, NE62° in the middle, and near EW in the east of the capital area. The regional tectonic stress field is characterized by horizontal compression.     

水作用下黄土土层锚杆的预应力损失

为研究水的作用下,土层锚杆的预应力损失,作者进行了土层锚杆抗拔模型试验。利用所得数据,得到了锚杆预应力损失随时间变化的曲线、预应力锚杆的锚头位移随时间而变化的曲线等。在对所得曲线分析与讨论的基础上,得出黄土土层锚杆的预应力损失主要是由于锚固段土层的蠕变引起的,而且随着土体含水量增加,土体的蠕变性也愈加明显,使得锚杆最终因锚固力不足而被拔出破坏。并提出施工过程中,注意排水、选择优质材料、保证安装质量,同时注重超张拉和二次张拉,是补偿预应力损失,确保工程安全性的重要手段。     

Analytical model for vertically loaded anchor performance with a bridle shank

Vertically loaded anchors offer an attractive alternative for mooring systems because of their relatively high efficiency and low cost. The bridle shank is an important feature of these anchors because its reconfiguration significantly affects their performance. A plasticity model considering a bridle shank is introduced to investigate the mechanism of the system. Model-based parametric studies on the effects of the bridle length, drag distance and anchor line angle are also conducted. These studies establish a new, more rational analytical model for these anchors, as well as contribute to the understanding of the mechanism of them in research and practice.     

系统锚杆对边坡岩体加固效果的数值模型试验研究

以大型的岩土工程数值分析软件AD INA为研究手段,对边坡岩体的分离块体经系统锚杆加固后,其抗压强度、弹性模量及c、值的提高,并计算和比较了锚固对不同强度岩体的参数影响大小,并对锚固岩体的各向异性进行了初步研究,垂直布锚对岩体的弹性模量影响较大,但是对于岩体的抗压强度的影响相对较小。