Stability analysis of a group of underground anhydrite caverns used for crude oil storage considering rock tensile properties

Tensile deformation and damage play an essential role in rock engineering problems. This paper presents a framework for evaluating the stability of a group of anhydrite caverns combining both experimental and numerical methods. In this study, the tensile Young’s modulus and Poisson’s ratio of anhydrite are determined based on the Brazilian disc splitting test. The tests show that the tensile Young’s modulus of anhydrite is less than the compressive Young’s modulus, with a ratio of approximately 0.58–0.91. The tensile Poisson’s ratio is greater than the compressive Poisson’s ratio, with a ratio of approximately 2.47–3.20. Based on the differences between the mechanical parameters (Young’s modulus, Poisson’s ratio) of anhydrite in the tensile and compressive states, a user-defined constitutive model is developed with the Hoek-Brown failure criterion, which describes the tensile and compressive behaviour at a laboratory scale. Finally, a large-scale three-dimensional (3D) anhydrite cavern group located in Anhui Province, China, which was formed by mining activity over the past 10 years, is used as a case study to illustrate the proposed framework. The model for the anhydrite cavern group is established in FLAC^3D5.0, and the stability of the anhydrite cavern group used for underground oil storage is then analysed with this model. The simulation results indicate that after the exploitation is completed, there are few plastic zones and tensile elements in the surrounding rock near the cavern group. The maximum value of cavern roof settlement is approximately 5.54 mm. The maximum cavern bottom upheaval is approximately 6.11 mm, and the maximum ground subsidence is approximately 3.0 mm. The results indicate that the Anhui Hengtai anhydrite cavern group possesses good stability potential as an underground oil storage space.

     

Performance Evaluation of GPU-Accelerated Spatial Interpolation Using Radial Basis Functions for Building Explicit Surfaces

This paper focuses on evaluating the computational performance of parallel spatial interpolation with Radial Basis Functions (RBFs) that is developed by utilizing modern GPUs. The RBFs can be used in spatial interpolation to build explicit surfaces such as Discrete Elevation Models. When interpolating with large-size of data points and interpolated points for building explicit surfaces, the computational cost would be quite expensive. To improve the computational efficiency, we specifically develop a parallel RBF spatial interpolation algorithm on many-core GPUs, and compare it with the parallel version implemented on multi-core CPUs. Five groups of experimental tests are conducted on two machines to evaluate the computational efficiency of the presented GPU-accelerated RBF spatial interpolation algorithm. Experimental results indicate that: in most cases, the parallel RBF interpolation algorithm on many-core GPUs does not have any significant advantages over the parallel version on multi-core CPUs in terms of computational efficiency. This unsatisfied performance of the GPU-accelerated RBF interpolation algorithm is due to: (1) the limited size of global memory residing on the GPU, and (2) the need to solve a system of linear equations in each GPU thread to calculate the weights and prediction value of each interpolated point.     

煤层开采对周边重要文物安全的影响研究

随着易采煤炭资源的日益枯竭,开采"三下"压煤显得非常急迫,如何在保证建筑物、基础设施等安全运行的前提下,合理地进行煤炭资源的开发是一个非常现实的重大课题.以郑家庄煤矿开采为例,在已有研究成果的基础上,首先采用自行研发的ROCK MODEL程序建立三维地质模型;然后采用概率积分法和数值模拟方法对多个开采方案进行分析计算,在综合考虑文物保护、地质条件、开采设计等因素的基础上,确定出最佳开采方案;其次采用综合研究手段,对采场上覆"两带"发育高度、断层、采动裂缝对近地表浅层含水层疏干和名树古木存活的可能性进行详细论证;最后提出具体防治措施.     

Comparative investigation of GPU-accelerated triangle-triangle intersection algorithms for collision detection

Efficient collision detection is critical in 3D geometric modeling. In this paper, we first implement three parallel triangle-triangle intersection algorithms on a GPU and then compare the computational efficiency of these three GPU-accelerated parallel triangle-triangle intersection algorithms in an application that detects collisions between triangulated models. The presented GPU-based parallel collision detection method for triangulated models has two stages: first, we propose a straightforward and efficient parallel approach to reduce the number of potentially intersecting triangle pairs based on AABBs, and second, we conduct intersection tests with the remaining triangle pairs in parallel based on three triangle-triangle intersection algorithms, i.e., the Möller’s algorithm, Devillers’ and Guigue’s algorithm, and Shen’s algorithm. To evaluate the performance of the presented GPU-based parallel collision detection method for triangulated models, we conduct four groups of benchmarks. The experimental results show the following: (1) the time required to detect collisions for the triangulated model consisting of approximately 1.5 billion triangle pairs is less than 0.5 s; (2) the GPU-based parallel collision detection method speedup over the corresponding serial version is 50x - 60x, and (3) Devillers’ and Guigue’s algorithm is comparatively and comprehensively the best of the three GPU-based parallel triangle-triangle intersection algorithms. The presented GPU-accelerated method is capable of efficiently detecting the potential collisions of triangulated models. Overall, the GPU-accelerated parallel Devillers’ and Guigue’s triangle-triangle intersection algorithm is recommended when performing practical collision detections between large triangulated models.

     

地热工程一体化非线性设计理论及工程应用

提出地热工程一体化非线性设计理论,该理论以面向工程对象为基本原则,注重资源配置、工艺过程 与设计参数的优化。详细介绍了该设计方法中的工程对象分析、对策设计、工艺设计与参数优化4个基本过程。 利用该理论进行了天津市奥林匹克中心中央空调的方案设计。     

Three-dimensional modeling of borehole data cored from engineering rock mass

Vast data from the drilling and geophysical prospecting are reliable original information to describe the space state of engineering rock mass, and one of the main difficulties in three-dimensional (3D) modeling of engineering rock mass is the processing of the primary data. From the view-point of 3D modeling, the engineering rock masses are classified as four basic types according to their geometric characteristics of geologic structure: (1) continuum rock mass; (2) discontinuous rock mass; (3) overturned fold rock mass and (4) intrusive rock mass. Because drilling data are very important to describe the characters of multi-scale of the spatial data for rock mass, the rule of how to process drilling data is developed to help appropriately display them in the viewpoint of 3D space. According to the characteristics of rock mass layers, the processing method of drilling data for 3D modeling of engineering rock masses, along with the layer thicknesses, is also proposed, including the evaluation rules and the extensive direction for original borehole data. By this method, the typical 3D data modeled is completed and the model form of the engineering rock mass is developed. By this example, it is finally verified that the method presented is successful and feasible to process 3D engineering rock mass. __________ Translated from Chinese Journal of Rock Mechanics and Engineering, 2005, 24(11): 1 821–1 826 [译自: 岩石力学与工程学报]     

褶皱岩体三维可视化构模技术及其工程应用

为解决由于褶皱岩体的边界面可能是非单值曲面给三维构模带来的困难,根据褶皱岩体的几何特征,提出了适合于褶皱岩体构模的数据模型,建造了面向对象的数据结构,开发了断面构模技术与三维可视化构模系统,并利用该系统建立了抚顺西露天矿北帮边坡岩体三维可视化模型。     

锚杆支护煤巷稳定性可靠度分析

 有些锚杆支护的煤巷曾发生过严重的冒顶,事故原因很复杂。其中煤巷支护设计与分析存在的问题有两个方面：一是煤巷围岩的物理、力学参数存在不确定性;二是稳定性设计分析的力学模型很多,各自只能从一个侧面反映其力学机理。为了对安全系数进行补充,考虑设计中的随机因素,在分析这些不确定性因素的基础上,根据巷道地压理论中的散体模型,锚杆支护结构抗力原理,研究了煤巷锚杆支护围岩稳定可靠度分析中抗力和荷载的计算方法,分析了某一锚杆支护煤巷的稳定可靠度,并认为锚杆支护的煤巷破坏失效概率在10%左右是可以接受的。     

A deep learning approach using graph convolutional networks for slope deformation prediction based on time-series displacement data

Neural Computing and Applications - Slope deformation prediction is crucial for early warning of slope failure, which can prevent property damage and save human life. Existing predictive models...     

土木工程专业结构力学教学与工程实际结合的探讨

结构力学是土木工程专业一门重要的专业基础课程,也是土木工程专业的核心课程,在整个专业培养计划中占有重要地位。结构力学基本概念较多,学生对抽象的理论教学内容往往感到难以理解。文章探讨了土木工程专业中结构力学教学与工程实际及后续专业课教学结合的问题,即理论教学与重大工程结合、课程内容与工程实际结合、计算简图与工程结构试验结合,有助于加深学生对结构力学基本概念的理解,提高学生运用结构力学知识解决工程实际问题的能力,为结构力学教学改革提供了参考。