千米深井大断面穿煤巷道“三锚”动态联合支护技术及应用

随着矿井开采深度的增加,矿山压力不断增大,尤其是千米深井大断面、穿煤巷道施工,传统的架棚支护工艺复杂、费用高、巷道维修量大,给安全生产带来困难。信湖煤矿根据实际情况,采用"三锚(锚杆、锚索、锚注)"动态联合支护技术,在-952回风石门揭穿3煤段进行实践,取得了良好的支护效果,为类似巷道的支护提供有益的参考和借鉴。

证券分析师盈利预测的锚定效应研究——来自中国A股上市公司的经验证据

锚定效应普遍存在于人们的决策过程中。证券分析师盈利预测是否存在锚定效应以及预测误差和锚定偏差之间的关系问题成为探索其预测模式的重点,以沪、深证券市场2008—2011年A股上市公司为样本进行实证分析,结果表明:证券分析师的盈利预测存在显著的锚定效应,且锚定值为公司上季(年)的实际盈利以及前期证券分析师一致性预测均值;证券分析师锚定偏差对其预测误差有显著影响,分析师根据动态锚不断调整修正盈利预测后,静态锚的影响逐渐减弱。

基于SOLIDWORKS的新型锚唇拉锚试验仿真分析

锚唇端面为平面时,锚爪会在锚机拉力下沿锚唇端面上滑。针对这一问题,提出一种新型的锚唇型式,利用三维软件SOLIDWORKS对拉锚过程进行动态仿真分析。仿真结果表明此种新型的锚唇型式可完全抑制锚爪向上滑移趋势。介绍了基于SOLIDWORKS的动态拉锚仿真流程及方法,提出了速度控制结合力控制的驱动方式,确保动态拉锚仿真的准确度。仿真分析的方法和结果可为其他锚唇的设计研究及拉锚仿真提供参考。

基于特征与区域定位增强的遥感舰船目标检测

高分辨率遥感图像在海上监视、海上搜救、海上运输等军用和民用领域的舰船检测方面有着广泛的应用。然而高分辨率光学遥感图像舰船目标检测通常存在背景复杂、目标方向任意、尺度多变等问题,导致检测精度不高。提出一种基于特征和区域定位增强的旋转检测算法RetinaNet-MPD。通过添加一个多尺度特征融合模块,充分融合不同尺度、不同层级的特征信息,以增强不同尺度特征图的特征表示能力。针对复杂背景下的舰船目标检测,提出极化双重注意力网络,通过在注意力网络后加入极化函数,充分提取目标的关键特征,同时抑制不相关信息,以有效区分目标和背景。此外,为更准确地定位舰船目标,在对正负样本进行训练时采用一种动态锚学习方法,从而动态选择目标区域内具有良好定位潜力的高质量锚,提高舰船目标检测精度。实验结果表明,RetinaNet-MPD算法在DOTA舰船和HRSC2016数据集上的检测精度分别为89.3%和85.8%,相比现有旋转目标检测算法的检测精度有所提升。

Factors affecting the dynamic response of pre-stressed anchors after transient excitation

The wide application of pre-stressed bolting technology in coal mine tunnels has made the nondestructive stress wave reflection method of determining bolting quality an important one. The effect of the support plate on the dynamic response of the pre-stressed anchor is of particular interest. A theoretical analysis and numerical simulations are used to identify the factors affecting the contact stress between the support plate and the rock wall. A formula allowing the calculation of contact stress is presented. Stress wave propagation through the nut, support plate, and rock wall are predicted. The dynamic response signals were measured in the field using prestressed anchors pre-tightened to different torques. The effects from the support plate on the dynamic response were recorded and the results compared to the predictions of pre-stressed anchor. This work provides a theoretical reference for the signal processing of dynamic reflected wave signals in anchor bolts.

A genetic algorithm for dynamic parameters reverse deduction of integrated anchorage system

In the analysis of the system of anchoring bar and wall rock in small strain and longitudinal vibration dynamic response, the influence of the cement grouting as well as the rock layer on the anchor bar can be evaluated as the two kinds of parameters: the dynamic stiffness and the damp, which are the vital reference of the anchorage quality. Based on the analytic solution to the dynamic equation of the integrated anchor bar, the new approach which combines genetic algorithm and the toolbox of Matlab is applied to solve the problem of multi-parameters reverse deduction for integrated anchorage system in dynamic testing. Using the traits of the self-organizing, self-adapting and the fast convergence speed of the genetic algorithm, the optimum of all possible solutions to dynamic parameters is obtained by calculating the project instances. Examples show that the method presented in this paper is effective and reliable.

Surrounding rock deformation regularity of roadway under extremely complicated geological conditions in deep mine and its control

By combining the practices of deep mine mining in Changguang Mine field and using the Universal Distinct Element Code 3 0(UDEC3 0) numerical computing method, the distribution characteristics of deformation field and stress field as well as the surrounding rock deformation regularity of soft rock roadway are analyzed under extremely complicated geological conditions, a technical principle of bolting to control the surrounding rock of roadway is put forward. And also using a dynamic control for surrounding rocks designing method, the supporting parameters and implement plan are rationally determined. The experimental tests have obtained a good controlling result of surrounding rock.

Basic dynamic characteristics and seismic design of anchorage system

Based on some assumptions,the dynamic governing equation of anchorage system is established.The calculation formula of natural frequency and the corresponding vibration mode are deduced.Besides,the feasibility of the theoretical method is verified by using a specific example combined with other methods.It is found that the low-order natural frequency corresponds to the first mode of vibration,and the high-order natural frequency corresponds to the second mode of vibration,while the third mode happens only when the physical and mechanical parameters of anchorage system meet certain conditions.With the increasing of the order of natural frequency,the influence on the dynamic mechanical response of anchorage system decreases gradually.Additionally,a calculating method,which can find the dangerous area of anchorage engineering in different construction sites and avoid the unreasonable design of anchor that may cause resonance,is proposed to meet the seismic precautionary requirements.This method is verified to be feasible and effective by being applied to an actual project.The study of basic dynamic features of anchorage system can provide a theoretical guidance for anchor seismic design and fast evaluation of anchor design scheme.