共查询到20条相似文献，搜索用时 109 毫秒
1.
在大规模深部岩体损伤过程中发生的裂隙尖端放电现象往往引发地下雷电,对该现象发生机理、表现规律的揭示有助于地震、岩爆等的临灾预报.不同于在岩土体中液固耦合界面上发生的自然电场异常机理,在岩土体内部发生的裂隙尖端放电可谓是引发自然电场异常的另一重要微观机制.本文基于现有裂隙尖端放电的研究成果,详细阐述了裂隙尖端放电发生的过程,解释了岩体损伤过程中自然电场异常产生的微观机理,并结合室内实验成果论述了自电位的主要特征;进行了理论推导,认为在大尺度岩体连续损伤过程中,自电位具有含脉冲状波动并整体下降的特征;开展了原位测试,结果证明人工采掘扰动下的深部岩体连续破坏的过程中,自电位在破坏前期缓慢下降,在破坏过程中会出现脉冲状波动,随着破坏程度的加剧整体呈现波动中下降的规律,与理论推导、室内实验结论都相符.对比室内实验和原位测试成果发现,随着研究目标的空间尺度由mm级别扩展到m的级别,自电位波动的幅值也从数十个mV扩展到数百甚至上千mV,故认为在利用自电位波动规律来预测岩体破坏状态时,须受研究对象的空间尺度的约束.此外,在原位测试中发现,自电位对岩体损伤过程的响应较直流电阻率而言具有时域上的超前优势,并对此现象进行了解释. 相似文献
2.
1988年10—11月间门头沟矿井下的慢速磁带记录系统共记到100多个事件,其中M_L=2.9的冲击地压为最大。通过地震记录图分析,我们发现这个冲击地压发生时和发生前十几小时,波通过震源区传播,波形发生畸变,S波波速增加、S波到时偏离正常情况。据非线性波动理论,我们认为这些现象是波通过非线性固体介质的直接效应。这些观测事实将为用微震记录监测冲击地压前的应力变化提供有力的理论依据。 矿山冲击地压和地震都是地壳内部岩体的不稳定性问题。它们有着以连续介质力学规律为基础的共同物理学本质。因此本文的结果不仅对矿山冲击地压的预报甚至对地震预报都是有意义的。 相似文献
3.
提出了几个难以用断层弹性回跳模型解释的地震实例，指出必须重视地壳上地幔结构的探测和深部流体的研究。然后用简单型说明，没有流体在存在，则不可能发生岩体间快速的错动。重点探讨发生在地壳内10-25km深处的强震孕育和发生机理，分析了深部流体的迁移和岩体的错动。最后结合实例，给出了在发生深部流体迁移的条件下，一次强震释放的能量和岩体错动的最大加速度。 相似文献
4.
采用混凝土塑性损伤本构模拟盾构管片,建立三维有限元壳-弹簧模型,开展了在45°断层错动下盾构隧道结构响应的静力弹塑性分析。研究表明,在正断层和逆断层错动下,衬砌受压损伤最大值均分布在拱顶处,衬砌受拉损伤最大值均分布在拱腰处;正断层错动下,环间螺栓易发生受拉破坏;逆断层错动下,混凝土管片易发生拉压损伤破坏。替换断层附近土体为软土的同时提高螺栓强度等级,可有效抵御较大的断层错动位移。研究对断层错动下盾构隧道的抗震措施具有一定参考价值。 相似文献
5.
6.
深部岩体处于"三高"环境下,表现出不同于浅埋岩体的性质,其变形破裂规律更为复杂(分区破裂、片帮、塑性流动、岩爆等),为了准确描绘深部隧道围岩变形破裂规律,采用PFC从微观角度研究深部岩体的宏观响应。研究发现:随着隧道埋深增加,压力增大,由浅部围岩表面塑性破坏变为深部围岩破裂扩展,破裂区域呈交替分区破裂向深部发展,破裂区的间距与岩性和埋深有关;从横断面看,拱腰先出现破裂,然后拱脚出现破裂,最后贯通形成破裂区;若围岩表面施加外力,破裂区域减小,分区向深部移动,因此预应力锚杆有效地改善了围岩承载特性;研究结果与模型试验吻合,符合深部岩体卸荷作用下的变形破坏规律。结论可为深部岩体工程设计施工提供参考。 相似文献
7.
多孔金属材料是一种新型功能和结构材料,具有良好的吸能、减震和阻尼特性。根据多孔金属材料的吸能特性,研究了多孔金属材料耗散能量准则,分析了多孔金属材料应用于冲击地压巷道支护的可行性。基于多孔金属材料的耗散能量准则,首次建立了刚柔吸能支护结构模型,将多孔金属材料应用于冲击地压巷道支护结构中,并利用FLAC 3D计算软件,对刚柔吸能支护巷道冲击破坏进行数值模拟。研究结果表明,刚柔吸能支护可高效吸收冲击能量、缓冲作用荷载及大幅度提高巷道围岩的可靠程度,是防治冲击地压发生和降低动力灾害的一种有效方法。 相似文献
8.
近断层地震动中长周期、短持时和高能量的加速度脉冲将对高层摩擦摆基础隔震结构的减震性能产生不利影响,考虑土-结构相互作用（SSI效应）后的隔震结构将产生动力耦合效应,可能进一步放大隔震结构地震响应。为此,通过一幢框架-核心筒高层摩擦摆基础隔震结构的非线性地震响应分析,考察近断层脉冲型地震动作用下框架-核心筒摩擦摆基础隔震结构的层间位移角、楼层加速度和隔震层变形等响应规律,揭示隔震体系的损伤机理。基于集总参数SR （sway-rocking）模型,分析不同场地类别与不同地震动类型对隔震体系动力响应影响规律。结果表明:高层摩擦摆基础隔震结构在近断层脉冲型地震动作用下的减震效果相比普通地震动减震效果变差,楼层剪力、层间位移角和隔震层变形等超越普通地震动作用下的1.5倍;对于Ⅲ和Ⅳ类场地类别,考虑SSI效应使隔震结构的地震响应进一步放大,弹塑性层间位移角随着土质变软增大尤为明显。 相似文献
9.
10.
大震以后,跟随着一系列的余震,其震源机制有的和主震一致,有的则大不一样,这表现在P波初动的反向,反应了震源应力场的变化。 余震震源机制变化的原因,既不是岩块的错动过头,也不是液体流出的下陷,而是发生大震的滑动岩块对其前后邻接岩块产生的转换应力场所引起的剪切破裂。 相似文献
11.
在研究岩浆岩和变质岩特点的基础上,根据岩浆岩岩体结构体的大小、有无缓倾的结构面及岩浆岩散粒状边坡岩体的特征,将岩浆岩边坡岩体结构划分为4大类7个亚类;根据部分正变质岩边坡岩体结构与岩浆岩边坡岩体结构类似,部分副变质岩中发育的板理、千枚理、片理类似沉积岩中的层理,以及边坡岩体具有似层状岩体结构的特征,把变质岩边坡岩体的结构划分为5大类11个亚类。岩体结构的划分为边坡稳定性研究、边坡病害治理及其工程效果评价提供了依据。 相似文献
12.
Stphane H&#x;rl 《地球表面变化过程与地形》2006,31(3):383-389
To aid rock art conservation, rock temperatures have been monitored at different depths and at low (30 min) and high (1 min) acquisition rates in a painted rock shelter in the uKhahlamba‐Drakensberg Park (South Africa). Preliminary data for winter (cold and dry) show that in that season cryoclasty is unlikely to occur (rare subzero thermal events and probable reduced moisture availability) and thermal shocks are improbable (highest measured ΔT/Δt < 2 °C min?1). High amplitude (about 30 °C) rock temperature cycles accompanied by reversals of the thermal gradient have been observed to occur almost daily and hint at the possibility of thermal stress fatigue. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
13.
Spatial Variability of the Depth of Weathered and Engineering Bedrock using Multichannel Analysis of Surface Wave Method 总被引：2，自引：0，他引：2
In this paper an attempt has been made to evaluate the spatial variability of the depth of weathered and engineering bedrock
in Bangalore, south India using Multichannel Analysis of Surface Wave (MASW) survey. One-dimensional MASW survey has been
carried out at 58 locations and shear-wave velocities are measured. Using velocity profiles, the depth of weathered rock and
engineering rock surface levels has been determined. Based on the literature, shear-wave velocity of 330 ± 30 m/s for weathered
rock or soft rock and 760 ± 60 m/s for engineering rock or hard rock has been considered. Depths corresponding to these velocity
ranges are evaluated with respect to ground contour levels and top surface levels have been mapped with an interpolation technique
using natural neighborhood. The depth of weathered rock varies from 1 m to about 21 m. In 58 testing locations, only 42 locations
reached the depths which have a shear-wave velocity of more than 760 ± 60 m/s. The depth of engineering rock is evaluated
from these data and it varies from 1 m to about 50 m. Further, these rock depths have been compared with a subsurface profile
obtained from a two-dimensional (2-D) MASW survey at 20 locations and a few selected available bore logs from the deep geotechnical
boreholes. 相似文献
14.
15.
16.
Ｔｈｅａｐｐｌｉｃａｔｉｏｎｏｆｍｉｃｒｏｗａｖｅｒｅｍｏｔｅｓｅｎｓｉｎｇｔｅｃｈｎｏｌｏｇｙｉｎｒｏｃｋ ｍｅｃｈａｎｉｃｓＮａｉ－ＧｕａｎｇＧＥＮＧ（耿乃光）；Ｚｈｅｎｇ－ＦａｎｇＦＡＮ（樊正芳）；Ｑｕａｎ－ＱｕａｎＪＩ（籍全权）；Ｃｈｅｎｇ－... 相似文献
17.
The remote sensing observational study for infrared radiation of rocks was proceeded during the loading on rocks until failure.
The major instruments used in experiments were transient spectrum apparatus, intelligent spectrum apparatus, infrared radiation
thermometer, infrared spectrum radiometer, and infrared thermal imaging system. The experiments for 26 kinds of rocks were
made. The studies show that infrared radiation temperature of rocks increases along with increasing of stress. The amplitude
of infrared radiation spectrum of rocks also increases along with increasing of stress. The observational results of infrared
thermal imaging of rocks are consistent with infrared radiation temperature. Before formation of major faults for some rocks,
the belt-shape thermal imaging of temperature anomaly displaies in position of future major faults. This study has led the
new technology of remote sensing into rock mechanics and tend to establish a new field in rock mechanics — remote sensing
rock mechanics (or remote sensing rock physics). The application of remote sensing rock mechanics in prediction of earthquake
and rock burst, and in measurement of stress field in rock mass is expected.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, Supp., 645–652, 1992.
Jin-Shen HAO, Ji-Han LI, Xiao-Hong LIU, Yi-Qiao ZHI, Jin-Kai ZHANG, Yong-Hong Lü, Yi LIU, Yun-Shen YU, He ZHANG, Quan-Quan
JI, Xiao-Fan ZHU and Ning CHEN took part in this work.
This subject is supported by the Chinese Joint Seismological Science Foundation (91006).
Work of Institute of Geophysics, SSB (93A0009). 相似文献
18.
Comparative study on CO2 sources in soil developed on carbonate rock and non-carbonate rock in Central Guizhou 总被引：1，自引：0，他引：1
In this paper, by using concentration and carbon stable isotope the CO2 sources of soil profiles developed on limestone, dolostone and claystone basements in Central Guizhou, China are comparatively studied. The results show that CO2 concentration of soil profiles developed on different basements is different, having the following sequence: limestone>dolostone>claystone. Below the soil depth of 20 cm from the surface the ? 13C value of CO2 in soil profile developed on limestone ranges from -12.811‰ - -13.492‰(PDB), that in soil profile developed on dolostone varys from -13.212‰ - -14.271‰(PDB) and that in soil profile developed on claystone is about -20.234‰ - -21.485‰(PDB). Taking the carbon isotope of soil organic matter and carbonate rock as two isotopic endmembers, the proportion of soil CO2 generated by dissolution of carbonate rock is calculated, about 21%-25% for soil profile developed on limestone basement, 19%-21% for soil profile developed on dolostone basement. There is almost no influx of CO2 generated by the dissolution of carbonate rock in soil profile developed on claystone basement. 相似文献
19.
Ali Ahmed Jalalh 《Acta Geophysica》2006,54(3):319-332
Pore volume compressibility is one of the physical properties of a reservoir that must be specified in many reservoir-engineering
calculations. In the presented research, the effect of compact pressure, temperature and porosity on compressibility was investigated.
A total of twenty-two different cores were tested: five limestone, one friable sandstone, fourteen medium to hard sandstone,
and two very dense sandstone. Core samples were placed in the test cell and subject to compacting pressure up to 10,000 psi.
Runs were made at room temperature and at 52°C for limestone samples.
Although there were some publications concerning measurement and study of the effect of pressure and temperature on pore volume
compressibility of reservoir rocks, nothing has been published about compressibility of Hungarian reservoir rocks, except
of the work of Tóth and Bauer (1988). The present study showed pore volume compressibility data for different Hungarian fields.
The result of the study at high temperature (52°C) shows that pore compressibility increases with increasing temperature. 相似文献
20.
Despite recent rapid advances in the field of structure-from-motion (SfM) photogrammetry, the use of high-resolution data to investigate small-scale processes is a relatively underdeveloped field. In particular, rock weathering is rarely investigated using this suite of techniques. This research uses a combination of traditional non-destructive rock weathering measurement techniques (rock surface hardness) and SfM to map deterioration and loss of cohesion of the surface using three-dimensional data. The results are used to interpret weathering behaviour across two different lithologies present on the site, namely shale and limestone. This new approach is tested on seven sites in Longyearbyen, Svalbard, where active weathering of a rock surface was measured after 13 years of exposure to extreme temperature regimes and snow cover. The surface loss was quantified with SfM and combined with rock surface hardness measurement distributions extrapolated in geographic information system (GIS). The combined results are used here to quantify the difference in response of both lithologies to these extreme temperatures. This research demonstrates the potential for further integration of SfM in rock weathering research and other small-scale geomorphological investigations, in particular in difficult field conditions where portability of field equipment is paramount. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd. 相似文献