基于三维激光扫描技术的开采下沉盆地可视化研究

获取不同时期三维地表点的空间位置是地面沉降监测的重要内容。三维激光扫描技术在沉降监测工程中可快速获取被测物体表面大量密集点的三维坐标信息,并在此基础上重构被测目标的三维模型。对三维激光扫描仪在地面沉降监测及获取地表三维模型进行了探讨,获取了矿区地表的三维精细模型,从而得到更准确、真实的塌陷区状况,为矿区地表沉降监测提供了新的方法,同时能为管理和决策层提供更加直接和真实的地表目标和研究对象,为矿区土地复垦和生态重建规划提供可靠的数据支持。

开采沉陷预计中参数误差对移动变形值的影响

针对开采沉陷预计中的概率积分法 ,分析了由于主要预计参数的误差而导致移动变形值的误差 ,并且分析了其对应的变化规律和关系。

基于双线性变化与多学习机器算法的矿山下沉估算比选模型

研究矿山地表最大下沉值的估算方法具有重要的安全生产意义,该研究的核心及关键问题在于提高估算的精度。本研究基于岩移数据决策、双线性变化及多种学习机器算法,对比筛选估算效果最优的矿山下沉估算方法。首先基于岩移数据决策方法,确定了采厚、倾角、平均采深、走向长度、倾向长度和覆岩岩性为最大下沉的影响参数;随后基于双线性变化的反推算模型,将倾角项转化为与其他参数相同时域数据以求提高估算精度;最后建立了C&RT、CHAID、Boosting Tree、Random Forest、BPNN和SVR等6种学习机器算法的估算模型。通过实例分析,CHAID和Random Forest方法返回了最差的估算结果,Boosting Tree和C&RT方法的估算结果会出现局部大残差值,BPNN估算时间数倍于其他方法,而SVR模型具有易于操作、耗时较短、精度较高的特点。故本研究认为SVR方法是一种高效可靠的最大下沉估算方法。

基于Relief算法与ReLU核ELM的煤矿开采最大下沉预测模型研究

尝试引入Re LU function核的ELM算法及Relief Algorithm对开采区最大下沉量进行预测。首先基于Relief Algorithm对现场岩移数据进行筛选优化;然后通过隐含层数目循环实验选出预测精度较高的ELM预测模型隐含层数目;再筛选优化后的参数为输入,最大下沉为目标分别建立基于Re LU function核、igmoid function核、Radial basis function核及Hardlim function核的ELM预测模型;最后对4种模型的预测结果进行对比分析。结果表明:采厚、平均采深、走向长度和倾向长度与最大下沉关系显著;以Re LU function核、隐含层神经元数目为57的ELM的预测结果精度显著优于对比组。

Analysis of factors and countermeasures of mining subsidence in Kaiyang Phosphorus Mine

Ground crack and subsidence were investigated in Kaiyang Phosphorus Mine as an example. Contribution factors to cause ground crack and mining subsidence were studied, including mining method, mining depth and ore thickness and stope size, dip angle of orebody, geological structure, nature of overburden and water contents, and roof supports, etc. Countermeasures against cracks and subsidence were put forward. The uniaxial compressive strength of compounded phosphorus gypsum after 28 d of curing period was tested to be more than 1 MPa. Phosphorus gypsum can be used as materials for the backfill of stope. By comparison and numerical simulation, cut and fill mining method with middle-deep drilling holes and ore transportation by blasting force was selected as the optimum mining method in Kaiyang Phosphorus Mine.

Research on mechanism of mountain landslide due to underground mining

The basics of mining landslides were first summed up based on the analysis ofactual materials by the application of mining subsidence and landslide theories. Further,the mechanism of along-layer landslide by mining was studied with the example of theXiangshan mining landslide at Hancheng, Shaanxi Province. Meanwhile, the state ofstress, and the mechanism of deformation and destruction of the Xiangshan mining slopewere analyzed by the Finite Element Method.

Influence and Control Strategy for Local Settlement for High-Speed Railway Infrastructure

This paper discusses the main impact factors of the local settlement and differential settlement of high- speed railway lines. The analysis results show that groundwater exploitation is the direct cause of differ- ential settlement. Based on the study of ballastless track additional load and of vehicle, track, and bridge dynamic responses under different differential settlements, a control standard of differential settlement during operation is proposed preliminarily.

Numerical Simulation of Land Subsidence at Tanggu District in Tianjin, China

Based on observed data from Tanggu District in Tianjin, a back-propagation neural network (BPNN) model was introduced to predict possible land subsidence due to exploitation of groundwater. According to model estimation under various hypothetical extraction scenarios, patterns of land subsidence at Tanggu District were studied and discussed.The predicted average background land subsidence rate of Tanggu is 9.47 mm/a.The significance of contribution of aquifers to land subsidence descends in order of units Ⅳ,Ⅲ,Ⅴ,Ⅱ.Land subsidence tends to deteriorate with the increase in total extraction rate.

The role of potential soil cavity on ground subsidence and collapse in coal mining area

Based on five basic assumptions, of the ground subsidence and collapse was using theoretical analysis method, the nature revealed from the mechanics point. Divided into four phases as groundwater level descent, soil cavity formation, soil cavity expansion, and ground collapse emersion, the whole process of ground subsidence and collapse was analyzed in detail. The study shows that ground subsidence and collapse is the macro- scopic performance and inevitable result of the soil cavity expansion and development, and the dynamic mechanics is the spalling force induced by the groundwater falling. The activities of underground water play a very important role in the process from the formation of soil cavity to the production of ground subsidence.

Land subsidence monitoring by D-InSAR technique

Nowadays, the researches of using Differential Interferometric Synthetic Aperture Radar (D-InSAR) tech- nique to monitor the land subsidence are mainly on how to qualitatively analyze the subsidence areas and values, but the analysis of subsidence process and mechanism are insufficient. In order to resolve these problems, 6 scenes of ERS1/2 images captured during 1995 and 2000 in a certain place of Jiangsu province were selected to obtain the subsidence and velocities in three time segments by ''two-pass'' D- InSAR method. Then the relationships among distributions of pumping wells, exploitation quantity of groundwater, and confined water levels were studied and the subsidence mechanism was systematically analyzed. The results show that using D-InSAR technique to monitor the deformation of large area can obtain high accuracies, the disadvantages of classical observation methods can be remedied and there is a linear relationship among the velocities of land subsidence, the water level and the exploitation quantity.

SAR-based Subsidence Monitoring and Assessment of the Factors Involved in the Occurrence of Subsidence,Lahore City

The judicious use and management of natural resources is vital to achieve sustainable development.Land and water are prime natural resources,and their depletion and degradation can lead to serious threats like land subsidence.Land subsidence is a phenomenon of the alteration of elevation at a point on the earth through the sinking of the surface.It occurs when the earth’s surface loses its support.The major causes of land subsidence include groundwater extraction,mining,construction overload,and other similar factors that increase pressure on the surface and eventually subsidize the land.Urban centers with excessive groundwater extraction and infrastructure development are at a high risk of subsidence.Lahore,the second-largest city in Pakistan,is undergoing an enormous increase in population density,uncontrolled urbanization with very large-scale construction projects,and intensive groundwater extraction which are responsible for subsidence directly or indirectly.Therefore,studies on groundwater status and unplanned urban appraisals have seriously urged monitoring of the subsidence in Lahore.Herein,we used freely available Sentinel-1 data for one year(from August 2018 to August 2019),with a high spatial and temporal resolution,to monitor subsidence in Lahore.The data were processed using the SNAP/Sta MPS approach for Persistent Scatterer Interferometric Synthetic Aperture Radar(PSI)analysis,which is an advanced InSAR technique.The displacement velocity map from InSAR processing shows a significant land deformation in the area with values ranging from-114 to 15 mm yr^(-1).Along with the Sentinel-1 data,we also used supplementary data obtained from various government agencies of Pakistan to study the land cover map,transportation network and waterways of Lahore,soil types,population density,and field points for assessing the results and understanding the roles of various factors in the occurrence of uplift or subsidence.A strong correlation was established between subsidence and various parameters such as groundwater extraction and lowering of the water table,soil type variations,land cover changes,surface water channels,and population density.The deformation map confirms the greatest subsidence in the central part of Lahore,while the uplift is observed in the less populated and rural areas situated near Ravi River.The land subsidence and uplift could be attributed to groundwater extraction and recharge through the canal system and the river,respectively.