龙滩水电站左岸蠕变体B区边坡位移监测分析

结合地下水位监测与降雨量监测结果,对龙滩水电站左岸蠕变体B区边坡位移监测资料进行综合分析,认为边坡蠕变岩体位移主要发生在高程520m以上,且强风化线或蠕变岩体折断面控制着边坡岩体的变形,由于边坡排水、坡体压脚,岩体变形速率逐渐变小,目前已经基本稳定。应加强边坡强风化线或蠕变岩体折断面附近的位移监测,特别是蓄水期监测;同时要保证地表和地下排水系统的正常运行。     

深圳地区全,强风化花岗岩承载力探讨

对《深圳地区建筑地基基础设计规程ＳＪＧ１－８８》中全、强风化花岗岩的划分和承载力值进行讨论，将全、强风化层各划出两个亚层，同时提出了各亚层的承载力及变形模量范围值。     

Behaviour of a rupture of the 21 June 2000 earthquake in South Iceland as revealed in an asphalted car park

A major earthquake (M=6.6) occurred on 21 June 2000, in South Iceland. This paper presents an unusual example of left-lateral strike-slip displacement recorded in a newly asphalted car park surface through a mechanically consistent pattern of open fissures and pressure ridges resulting from simple shear and rotation. Measurement of these features allows accurate reconstruction of the local deformation. The behaviour of the asphalt layer resembles that of analogue physical models, especially in terms of rotations induced by shear deformation. It is finally shown that through a wide range of scales some basic patterns associating rotation and opposite senses of strike-slip exist in the South Iceland Seismic Zone.     

From geometry to dynamics of microstructure: using boundary lengths to quantify boundary misorientations and anisotropy

The microstructure of a quartzite experimentally deformed and partially recrystallised at 900 °C, 1.2 GPa confining pressure and strain rate 10⁻⁶/s was investigated using orientation contrast and electron backscatter diffraction (EBSD). Boundaries between misoriented domains (grains or subgrains) were determined by image analysis of orientation contrast images. In each domain, EBSD measurements gave the complete quartz lattice orientation and enabled calculation of misorientation angles across every domain boundary. Results are analysed in terms of the boundary density, which for any range of misorientations is the boundary length for that range divided by image area. This allows a more direct comparison of misorientation statistics between different parts of a sample than does a treatment in terms of boundary number.The strain in the quartzite sample is heterogeneous. A 100×150 μm low-strain partially recrystallised subarea C was compared with a high-strain completely recrystallised subarea E. The density of high-angle (>10°) boundaries in E is roughly double that in C, reflecting the greater degree of recrystallisation. Low-angle boundaries in C and E are produced by subgrain rotation. In the low-angle range 0–10° boundary densities in both C and E show an exponential decrease with increasing misorientation. The densities scale with exp(−θ/λ) where λ is approximately 2° in C and 1° in E; in other words, E has a comparative dearth of boundaries in the 8–10° range. We explain this dearth in terms of mobile high-angle boundaries sweeping through and consuming low-angle boundaries as the latter increase misorientation through time. In E, the density of high-angle boundaries is larger than in C, so this sweeping would have been more efficient and could explain the relative paucity of 8–10° boundaries.The boundary density can be generalised to a directional property that gives the degree of anisotropy of the boundary network and its preferred orientation. Despite the imposed strain, the analysed samples show that boundaries are not, on average, strongly aligned. This is a function of the strong sinuosity of high-angle boundaries, caused by grain boundary migration. Low-angle boundaries might be expected, on average, to be aligned in relation to imposed strain but this is not found.Boundary densities and their generalisation in terms of directional properties provide objective measures of microstructure. In this study the patterns they show are interpreted in terms of combined subgrain rotation and migration recrystallisation, but it may be that other microstructural processes give distinctive patterns when analysed in this fashion.     

A model for multiphase flow and transport in porous media including a phenomenological approach to account for deformation—a model concept and its validation within a code intercomparison study

Multiphase flow processes in unsaturated cohesive soils are often affected by deformation due to swelling and shrinking as a result of varying water contents. This paper presents a model concept which is denoted ‘phenomenological’ in terms of the processes responsible for soil deformation, since the effects of deformation on flow and transport are only considered by constitutive relations that allow an adaptation of the hydraulic properties. This new model is validated in a detailed intercomparison study with two state-of-the-art models that are capable of explicitly describing the processes relevant for the deformation. A ‘numerical experiment’ with a state-of-the-art reference model is used to produce ‘measurement data’ for an inverse-modelling-based estimation of the model input parameters for the phenomenological concept.     

基于变形分区确定某反倾岩质岸坡变形体锁固段

对处于蠕滑阶段的边坡而言,准确确定蠕滑段和锁固段是进行稳定性评价及演化趋势预测的基础和前提。以我国西南山区某水库型岸坡变形体为例,在综合分析岸坡工程地质条件的基础上,通过联合运用野外现场地质调查、地表位移监测、钻孔、平硐、深部位移监测、物探等多种勘察手段,查明了岸坡的结构特征,并分别对岸坡进行地表和深部变形分区。 在此基础上,结合当前稳定性现状,划分出岸坡蠕滑段与锁固段。结果表明:(1)岸坡在河谷下切过程中发生了弯曲倾倒变形,弯曲折断面深度为20～80m;(2)岸坡前部为蠕滑段,中部为锁固段,后部为拉裂段,具备滑移-拉裂-剪断三段式发育特征。研究结果可直接用于该岸坡变形体的稳定性评价,且对于同类型处于蠕滑阶段边坡的勘察手段及综合分析具有一定的借鉴意义。     

岩脉多次侵入条件下斜坡变形破坏模式及稳定性分析

岩质斜坡受到花岗岩脉的多次侵入,坡体结构和岩体结构均有较大的改变,因此斜坡的变形破坏模式和稳定性均有可能发生变化。本文以雅砻江中游楞古水电站坝址区嘎夏帕斜坡为例,对多次花岗岩脉侵入条件下斜坡的变形破坏模式和稳定性进行分析。嘎夏帕斜坡原本为陡倾中薄层砂岩组成的逆向坡,岩体完整性较好,稳定性较高; 由于受到花岗岩脉的多次侵入,坡体变成砂岩和岩脉互层的结构,在岩脉挤压作用下,大部分岩体呈碎裂状,完整性差,坡体的变形模式由弯曲-倾倒式变为挡墙溃决式。中部完整性较好的砂岩成为挡墙,和前部岩脉一起阻止后部大方量碎裂状岩体下滑,但是随着前部脉体的失稳破坏,斜坡有可能发生挡墙溃决式整体滑坡。并通过数值模拟软件3DEC进行了验证,计算结果与定性分析一致。本文的结论可以为此类斜坡的稳定性分析和防治提供理论支持,具有一定的参考价值和实际意义。     

面理弯切轴测量技术在造山带研究中的应用——以美国阿肯色河地区为例

基于变形分解理论提出的面理弯切轴测量技术,通过对变斑晶中多期面理的测定分析,为厘定造山运动中的变形过程提供了新的精确定量研究手段。面理弯切轴数据已经被用于解决地质领域多种问题,例如:研究造山运动过程中变形变质历史以及在区域和造山带尺度对比多期变质作用;论证变斑晶生长过程是否发生旋转;变斑晶成核生长与区域变形过程之间的关系;重建板块运动历史过程;约束不同地质事件的发生时限;划分复杂变形分解类型以及岩浆侵位机制及时限研究。本文主要介绍面理弯切轴测量方法的原理、具体测定方法、研究意义及应用范围,并以美国阿肯色地区为例,详细介绍了面理弯切轴测量技术在造山运动过程区域变形历史重建中的应用。     

Neoglacial (<3000 years) till and flutes at Saskatchewan Glacier,Canadian Rocky Mountains,formed by subglacial deformation of a soft bed

Understanding the processes that deposit till below modern glaciers provides fundamental information for interpreting ancient subglacial deposits. A process‐deposit‐landform model is developed for the till bed of Saskatchewan Glacier in the Canadian Rocky Mountains. The glacier is predominantly hard bedded in its upper reaches and flows through a deep valley carved into resistant Palaeozoic carbonates but the ice margin rests on a thick (<6 m) soft bed of silt‐rich deformation till that has been exposed as the glacier retreats from its Little Ice Age limit reached in 1854. In situ tree stumps rooted in a palaeosol under the till are dated between ca 2900 and 2700 yr bp and record initial glacier expansion during the Neoglacial. Sedimentological and stratigraphic observations underscore the importance of subglacial deformation of glaciofluvial outwash deposited in front of the advancing glacier and mixing with glaciolacustrine carbonate‐rich silt to form a soft bed. The exposed till plain has a rolling drumlinoid topography inherited from overridden end moraines and is corrugated by more than 400 longitudinal flute ridges which record deformation of the soft bed and fall into three genetically related types: those developed in propagating incipient cavities in the lee of large subglacial boulders embedded in deformation till, and those lacking any originating boulder and formed by pressing of wet till up into radial crevasses under stagnant ice. A third type consists of U‐shaped flutes akin to barchan dunes; these wrap around large boulders at the downglacier ends of longitudinal scours formed by the bulldozing of boulders by the ice front during brief winter readvances across soft till. Pervasive subglacial deformation during glacier expansion was probably facilitated by large boulders rotating within the soft bed (‘glacioturbation’).     

衡山界牌倾滑韧性剪切带的变形特征与应变分析

本文在前人工作的基础上,通过大量的第一手资料,对衡山界牌倾滑韧性剪切带（以下简称该带）的分带、变形特征、形成环境进行了探讨;对该带的几何学、运动学特点进行了分析,计算了该带的变应程度和位移量,并探讨了该带的成因及演化模式。