Modelling the flexural buckling failure of stratified rock slopes based on the multilayer beam model

The buckling failure of stratified rock slopes intersected by a set of steep discontinuities that are approximately parallel to the slope surface is frequently encountered while constructing railways and roadways in mountainous areas. In this study, an analytical approach based on the energy equilibrium principle is presented to solve the flexural buckling stability of stratified rock slopes within the framework of multilayer beam theory. The generalized HoekBrown failure criterion is introduced to reflect the influences of slope size(scale effects) on the buckling stability. Subsequently, numerical and physical modellings from previous literatures are employed to validate the proposed approach. Furthermore, a practical case of Bawang Mountain landslide is also used for the comparative analysis. The study shows that the present analytical approach is capable to provide a more reasonable assessment for the buckling failure of stratified rock slopes, compared with several existing analytical approaches. Finally, a detailed parametric study is implemented, and the results indicate that the effects of rock strength, rock deformation modulus, geological strength index, layer thickness and disturbance degree of rock mass on the buckling failure of stratified rock slopes are more significant than that of rock type and slope angle.     

2016年门源Ms6.4地震前祁连山周边断层活动分析

基于青藏高原东北缘地区最新的跨断层资料,利用时序曲线分析、断层速率合成分析和垂直形变累积率分析等多种方法进行计算,从不同角度和范围提取2016年门源Ms6.4地震震前异常特征,揭示断层活动。结果显示：1）震中距150 km以内多个场地出现了典型的以加速张性变化为主的短期异常,150~300 km内的异常以趋势变化为主;2）祁连山-海原断裂带上异常场地的空间分布表现出由祁连山断裂带中部集中向东迁移至中东部集中的特征,海原断裂上异常有所增多,此类现象与2003年民乐6.1级地震前的现象极其相似;3）祁连山断裂自2014年以来合成速率偏离正常动态值较远,容易积累应变。垂直形变趋势累积率的计算结果显示,地震震中位于形变积累的高值区。     

航空重力测量中牛顿中心差分器对确定载体加速度的影响

讨论不同点数的牛顿中心差分器对航空重力测量中确定载体加速度的影响。理论分析表明,当航空重力测量的有效频段位于牛顿中心差分器的通带时,不同点数的牛顿中心差分器所得结果经低通滤波后几乎没有差异。实验表明,当采样间隔为1 s、载体平均速度为155 m/s、所需重力数据的分辨率为10 km时,低通滤波后不同点数的牛顿中心差分器输出结果之间的较差优于2.1 mGal。     

基于Android的移动端宗地图成图

宗地图是土地使用合同书附图及房地产登记卡附图,也是矿区土地管理的附图。利用移动端进行宗地图现场成图有利于土地所有者与矿区土地管理部门对宗地信息进行现场核查。本文在对Android系统研究的基础上搭建PC环境下Android开发的虚拟环境,采用开源的Java技术开发宗地图自动生成模块。该模块能够实现绘图区的定义、宗地图基础数据的录入、宗地图界址点坐标的展绘等功能。该模块以图斑为基本分析单元,能够快速、合理、美观地展绘界址点并标注宗地图要素,从而提高了土地管理部门的办公效率。     

改进的小波阈值函数对变形监测数据的去噪研究

基于小波分析中传统的阈值函数,结合其他学者提出的小波阈值函数,提出一种改进的小波阈值函数,并将其应用于变形监测数据的去噪处理。理论分析和算例表明,新的小波阈值去噪函数能够有效去除噪声。     

城镇-农业-生态空间划定的多情景模拟

城镇-农业-生态空间划定(简称"三区"划定)是国土空间规划的核心内容,对于科学合理地规划、利用有限的国土资源具有重要的意义。已有研究主要根据区域内土地利用与社会经济发展现状构建指标体系进行"三区"划定,较少将未来土地利用变化纳入"三区"划定过程中,使得划定结果在指导实践过程中缺乏前瞻性。针对这一问题,本文提出一种基于土地利用情景模拟,结合指标体系评价与决策树特征挖掘的"三区"划定方法,并以武汉市2015年土地利用现状为基础,在土地利用变化情景模拟的基础上进行"三区"划定。通过对比,验证了本文提出方法的合理性。研究发现:①不同情景下的"三区"空间在规模、空间分布上具有明显差异,将未来土地利用变化纳入"三区"划定过程中确有必要;②不同土地利用情景下"三区"空间的差异主要出现在三类空间的交界区域,这些区域是国土空间规划应该关注的重点区域。     

基于PDA的测量机器人自动化网观测软件研究

分析了自动化网观测软件的具体开发过程,介绍了软件系统所实现的主要功能,获得了可靠的观测数据.     

基于资源三号三线阵影像快速制作DSM生产应用研究

主要利用资源三号卫星影像进行稀少控制定向和选择不同视影像组合分别进行DSM产品快速制作试验,并对试验结果进行主观和定量评价,分析利用资源三号三线阵影像快速制作DSM产品的流程及适用条件。     

Seasonal and annual variations of marine sinking particulate flux during 1993~1996 in the central South China Sea

A total of 67 samples from the upper and lower sediment traps in the central South China Sea were analyzed, which were collected during 1993~1996. It is indicated that the distribution of stable isotope values, surface primary productivity, fluxes of total particulate matter, carbonate, biogenic opal, organic carbon, planktonic foraminiferal species and their total amount exhibit obviously seasonal and annual fluctuations. High values of the fluxes occurred in the prevailing periods of the northeastern and southwestern monsoons, and the low values occurred during the periods between the two monsoons. The fluxes of some planktonic foraminiferal species (Globigerinoides sacculifer, G. ruber, Globigerinita glutinata, Neogloboquadrina dutertrei) and their percentages also exhibit two prominent peaks during the prevailing periods of the northeastern and southwestern monsoons respectively, while those of Globigerina bulloides, Globorotalia menardii and Pulleniatina obliquiloculata only exhibit one peak in the prevailing periods of the northeastern monsoon. In addition, fluxes and percentages of Globigerinoides sacculifer and Globorotalia menardii as well as the fluxes of carbonate and total amount of planktonic foraminifera decrease gradually from 1993 to 1996, and those of Globigerina bulloides, Globigerinita glutinata and biogenic opal increase gradually from 1993 to 1996. The fluxes of carbonate and organic carbon in the upper trap are higher than those in the lower one. The study indicates that the seasonal and annual variations of the sediment fluxes and planktonic foraminiferal species are mainly controlled by the changes of surface primary productivity and hydrological conditions related to the East Asian monsoon. The lower carbonate and organic carbon fluxes in the lower trap are related to the dissolution.     

难浸金矿石电场强化电离—氰化提金试验

对硫、砷、炭（泥）含量较高的难浸金矿石,采用电场强化电离－氰化提金新工艺进行试验,从理论上对方法原理者了讨论,并通过试验对比,证明该方法较规氰化提金方法提高了金浸出率（８％～８０％）,缩短了浸出周期（为原周期的１／４～２／３）。经野外堆浸试验,肯定了方法的可行性。