B8S的解析化附件——BSS-AAB的机械配置研究

本文介绍了模拟测图仪B8S的解析化改造附件B8S-AAB的原理、组成和特点。对B8S-AAB的机械配置进行了重点研究和分析，并进行了必要的精度论征，最后给出了改造后仪器的使用测试结果。     

地表物质迁移的构成特征及其地域变化

提出地表物质迁移构成特征的概念及其指标，动用我国东部季风影响范围内近６０条河流的资料，探讨了地表质迁移构成特征与影响因子的关系，并研究了我国地表物质迁移构成特征随纬度的变化。     

极端干旱地区清绿线K170段铁路沙害机械措施治理

清绿线Ｋ１７０段铁路地处极端干旱区，植物固沙难度大，铁路沙害的治理宜采用机械措施综合防治体系。２年的防护效益观测证实，用草方格沙障固沙，２０ｃｍ高度风速可比流沙区降低７６．３％，层内输沙率仅为流沙区的０．２８％；用砾石覆盖措施固沙，相应防护效果依次为１９．０９％和０．９１％；各防护措施下的风沙流特征值Ｑ６～２０／Ｑ０～６，都达到了＞１的有效防护指标。     

粘弹性岩体力学模型识别与参数反演解析方法研究

本文基于圆形和非圆形隧道围岩粘弹性位移反演分析解析方法的最新进展，根据隧道围岩力学参数解析解的反演规律，提出了五个粘弹性力学模型识别与参数定理，并通过算例和工程实例对所给出的定理作了必要的验证。     

A semi-analytical method of stress-strain analysis of buried steel pipelines under submarine landslides

A semi-analytical method of the stress-strain analysis of buried steel pipelines under submarine landslides was proposed, considering the nonlinearities of the pipe-soil interaction and mechanical properties of the pipe steel. The pipeline was divided into three parts according to different loading conditions, and the corresponding differential equations were established based on a combination of the beam-on-elastic foundation and elastoplastic-beam theories. According to the second-order central difference method, the transverse horizontal displacement was calculated, and then the bending strain was obtained based on the relation between bending strains and curvatures. Considering the interaction between the axial and bending strains, the axial strain can be derived from the equilibrium condition by equating the axial force. The proposed method was verified through the comparison of obtained solutions to ANSYS results, with minor deviations which do not exceed about 4.6%. Additionally, the effects of the slide width, the buried depth of pipelines, the internal friction angle of soils, the cohesion of soils and the bulk density of soils are investigated through parametric studies.     

Impact of mechanical heterogeneity on joint density in a welded ignimbrite

Joints are conduits for groundwater, hydrocarbons and hydrothermal fluids. Robust fluid flow models rely on accurate characterisation of joint networks, in particular joint density. It is generally assumed that the predominant factor controlling joint density in layered stratigraphy is the thickness of the mechanical layer where the joints occur. Mechanical heterogeneity within the layer is considered a lesser influence on joint formation. We analysed the frequency and distribution of joints within a single 12-m thick ignimbrite layer to identify the controls on joint geometry and distribution. The observed joint distribution is not related to the thickness of the ignimbrite layer. Rather, joint initiation, propagation and termination are controlled by the shape, spatial distribution and mechanical properties of fiamme, which are present within the ignimbrite. The observations and analysis presented here demonstrate that models of joint distribution, particularly in thicker layers, that do not fully account for mechanical heterogeneity are likely to underestimate joint density, the spatial variability of joint distribution and the complex joint geometries that result. Consequently, we recommend that characterisation of a layer’s compositional and material properties improves predictions of subsurface joint density in rock layers that are mechanically heterogeneous.     

太行山地壳厚度转变带动力学不稳定与前缘盆地构造挤压的关系

太行山是我国最大地壳厚度转变带之一. 本文从地壳厚度转变带动力学不稳定性出发，应用地壳黏-弹性、幂律流体本构关系开展了二维有限元模拟. 结果表明，由于山西高原重力荷载，太行山地壳厚度转变带将发生下地壳黏性流变，下地壳流变将导致盆地区中、下地壳动力学性质脱耦，形成中、下地壳间近水平剪切. 这一剪切是诱发上地壳有效水平挤压应力在地壳厚度转变带不断减小、在盆地内不断增大的主要原因. 经8.6 Ma后，在3 km高原重力作用下，盆地区上地壳可形成约30 MPa近水平挤压. 华北东部盆地北西西-南东东的挤压主要受太行山地壳厚度转变带下地壳流变所造成的动力学制约，与区域板块作用导致的远程应力场可能无直接联系.     

Forced vibrations of a beam elastically restrained against rotation and carrying a spring–mass system

An exact solution for the title problem is obtained in closed form fashion in the case of a Bernoulli–Euler beam. It is assumed that the exciting force is applied to the mass which is elastically mounted on the beam. The mathematical model constitutes a first order approximation to a motor or engine elastically mounted on a structural element. The operation of the machine generates a transverse, sinusoidally varying force. The problem is of basic interest in mechanical, naval and ocean engineering systems from the point of view of the determination of dynamic displacements and stresses; sound radiation calculations, etc. The present problem arose in connection with the mounting of an engine on a structural beam in a small naval vessel and when excessive vibrational level was noted. This study was undertaken in order to understand the physical problem and to correct the mechanical situation     

Physical and Mechanical Characteristics of Seabed Sediment Microstructure in the Northern Shelf of the South China Sea

In the present work, the scanning electron-microscopic observations, electronprobing (energy spectrum) analyses and the analyses of physico-mechanical parmeters have been made for the sediments from two areas of the South China Sea Shelf (i.e., the sea area off the Pearl River mouth and the sea area to the south of Hainan Island); the relaion between the microstructures and the geotechnical (engineering) properties of the shelf seabed sediments has been investigated. Results of analyses reveal the diversity of the micro-structures of sediment and lead to a preliminary micro-structures classification. According to the packing and interconnecting (mutual cotacting) styles of sediment grains, the structure of pores and based on the physical and mechanical parameters, it is possible to comprehensively assess the engineering property of the microenvironments of marine sediments.     

盆山地壳横向变化对挤压构造变形的影响——来自砂箱模拟实验的启示

前陆克拉通与造山带增生楔在地壳结构、力学性质等方面有明显的差异。挤压作用使盆山地壳横向变化通过构造变形表现出来。本文设计了具有深浅两个滑脱层"克拉通"与不同能干性的"造山楔"接触砂箱模型,通过模拟实验分析了盆山地壳横向差异变化对挤压构造变形的影响。实验结果表明,端部的挤压收缩位移由刚性的"克拉通"推挤相对软弱的"造山楔"使之形成挤压"冲起构造",而"造山楔"发生收缩变形的同时也斜向推挤刚性的"克拉通",并通过克拉通内部的滑脱层将收缩应变向克拉通内部传递。受不同深度滑脱层发育的影响,"克拉通"发育分层不协调收缩变形。在挤压作用下,随着"造山楔"与"克拉通"地壳在横向上能干性差异的增加,"造山楔"收缩形成的"冲起构造"幅度减小,而向"克拉通"侧向(斜向)挤压形成的"反冲构造"幅度增加,"造山楔"通过深层滑脱层向"克拉通"传递收缩应变的调节能力减弱,通过浅层滑脱层向"克拉通"传递收缩应变的调节能力增强。"造山楔"由深层过渡至浅层形成强变形带,由"克拉通"边缘至内部形成的深层冲断褶皱与浅层褶皱冲断组合过渡为深层褶皱与浅层的褶皱冲断组合,"克拉通"边缘的冲断带由深层的前展式楔状逆冲叠瓦扇构造向"克拉通"内部的浅层褶皱组合过渡。实验结果为理解中国西北部复杂山前冲断带构造的形成机制具有启示作用。