采空侧巷道底鼓形成机制与防治技术研究   总被引：2，自引：1，他引：1  

初明祥  王清标  夏均民 《岩土力学》2011,32(Z2):413-417

煤矿深部采空侧巷道底鼓现象日趋普遍和严重,严重影响巷道的运输和正常使用,其底鼓防治技术研究已成为目前煤矿岩石力学问题研究的重点。通过理论分析、数值模拟、现场试验等研究方法,对采空侧巷道底鼓的特征、形成原因、形成机制及其防治技术进行了详细研究,得到以下结论：（1）采空侧巷道底鼓与底板岩性和底板岩层的应力重新分布有关;（2）底板在严重挤压变形的情况下发生断裂,底板隆起,墙角发生外移是造成底鼓的主要原因;（3）底鼓始于巷道底角与底板中部;（4）采用中空锚杆注浆与高强锚杆锚注联合支护技术能有效治理采空侧巷道的底鼓  相似文献   

Dangerous deformations of subgrade and methods of their calculation     

Alexander Isakov 《寒旱区科学》2013,5(4):0353-0362

The main reasons for a breach of trouble-free operation of the subgrade are the different kinds of deformation, such as train load impact on subgrade surface, loss of stability to subgrade slope, weight of embankment on the base, and partial or complete failure of the railway track due to frost heaving. This paper gives a summary of deformation analysis methods being developed in Russia to estimate the operating conditions of the railway subgrade.  相似文献   

Revision of thickness design of cylindrical frozen walls considering frost heave     

XiaoMin Zhou  AnBao Wang  HuaDong Guan 《寒旱区科学》2013,5(5):0591-0595

This paper outlines development of the thickness design of cylindrical frozen walls in artificial ground freezing (AFG). A plain strain mechanical model coupled with infinite surrounding soil and rock ...  相似文献   

孟加拉笛鲷与四带笛鲷的微卫星分析     

李培  王中铎  郭昱嵩  刘丽  刘楚吾 《台湾海峡》2011,30(4):517-521

采用聚丙烯酰胺凝胶电泳技术,从西大西洋笛鲷（Lutjanuscampechanus）和勒氏笛鲷（L．russel—lii）的微卫星引物中筛选出适用于孟加拉笛鲷（L．bengalensis）和四带笛鲷（三．kasmira）的微卫星引物,并应用于三亚和湛江群体的遗传结构分析．结果表明：25对引物中筛选出13对可以稳定扩增出特异片段的引物,其中12对可在孟加拉笛鲷基因组中扩增出重复性好的特异性条带;10对可在四带笛鲷中扩增出重复性好的特异性条带,并且全部呈现出种内多态;9对为两个种通用．孟加拉笛鲷的湛江群体（zMJ）和三亚群体（SMJ）、四带笛鲷的湛江群体（ZSD）和三亚群体（SSD）的平均等位基因数分别为：3．8889、4．1111、4．3333、4．2222;平均观测杂合度分别为：0．5833、0．6389、0．5944、0．6389;平均多态信息含量分别为：0．4720、0．4692、0．5474、0．5257．将本实验所得结果与笛鲷鱼其他研究结果进行比较分析,可以看出目前湛江海域野生笛鲷的遗传多样性整体比较丰富,但部分野生笛鲷已表现出杂合子缺失的趋势,这势必会引起将来遗传多样性的降低,所以要尽旱对野生群体进行摸底调查。并找出解决养殖群体污染野生群体这一问题的方法．  相似文献   

A semi-analytical solution for frost heave prediction of clay soil     

Hui Bing  Ying Zhang  GuoYu Li 《寒旱区科学》2014,6(5):0499-0503

Frost heave is one of the main freezing problems for construction in permafrost regions.The Konrad-Morgenstern segregation potential（SP） model is being used in practice for frost heave using numerical techniques.However,the heat release from in-situ and migrated water in the freezing zone could result in some numerical instability,so the simulation of frost fringe is not ideal.In this study,a semi-analytical solution is developed for frost heave prediction of clay soil.The prediction results to the two tests with different freezing mode with clay soil agree well with the tested behavior,which indicates the feasibility of the solution.  相似文献   

Basal‐topographic control of stationary ponds on a continuously moving landslide     

Jeffrey A. Coe  Jonathan P. McKenna  Jonathan W. Godt  Rex L. Baum 《地球表面变化过程与地形》2009,34(2):264-279

The Slumgullion landslide in the San Juan Mountains of southwestern Colorado has been moving for at least the last few hundred years and has multiple ponds on its surface. We have studied eight ponds during 30 trips to the landslide between July 1998 and July 2007. During each trip, we have made observations on the variability in pond locations and water levels, taken ground‐based photographs to document pond water with respect to moving landslide material and vegetation, conducted Global Positioning System surveys of the elevations of water levels and mapped pond sediments on the landslide surface. Additionally, we have used stereo aerial photographs taken in October 1939, October 1940 and July 2000 to measure topographic profiles of the eight pond locations, as well as a longitudinal profile along the approximate centerline of the landslide, to examine topographic changes over a 60‐ to 61‐year period of time. Results from field observations, analyses of photographs, mapping and measurements indicate that all pond locations have remained spatially stationary for 60–300 years while landslide material moves through these locations. Water levels during the observation period were sensitive to changes in the local, spring‐fed, stream network, and to periodic filling of pond locations by sediment from floods, hyperconcentrated flows, mud flows and debris flows. For pond locations to remain stationary, the locations must mimic depressions along the basal surface of the landslide. The existence of such depressions indicates that the topography of the basal landslide surface is irregular. These results suggest that, for translational landslides that have moved distances larger than the dimensions of the largest basal topographic irregularities (about 200 m at Slumgullion), landslide surface morphology can be used as a guide to the morphology of the basal slip surface. Because basal slip surface morphology can affect landslide stability, kinematic models and stability analyses of translational landslides should attempt to incorporate irregular basal surface topography. Additional implications for moving landslides where basal topography controls surface morphology include the following: dateable sediments or organic material from basal layers of stationary ponds will yield ages that are younger than the date of landslide initiation, and it is probable that other landslide surface features such as faults, streams, springs and sinks are also controlled by basal topography. The longitudinal topographic profile indicated that the upper part of the Slumgullion landslide was depleted at a mean vertical lowering rate of 5.6 cm/yr between 1939 and 2000, while the toe advanced at an average rate of 1.5 m/yr during the same period. Therefore, during this 61‐year period, neither the depletion of material at the head of the landslide nor continued growth of the landslide toe has decreased the overall movement rate of the landslide. Continued depletion of the upper part of the landslide, and growth of the toe, should eventually result in stabilization of the landslide. Published in 2008 by John Wiley & Sons, Ltd.  相似文献   

非均质软土基坑抗隆起稳定性的极限分析方法   总被引：6，自引：0，他引：6  

秦会来  黄茂松  王卫东 《岩土力学》2008,29(10):2719-2724

考虑到实际工程中土体非均质以及软土地区基坑开挖过程中土体稳定性的特点,将极限分析上限方法应用于非均质软土基坑抗隆起稳定分析计算中,讨论了极限分析方法的适用性问题。选用Prandtl机构建立了非均质软土地区基坑抗隆起稳定分析的运动许可速度场,根据速度场推导了极限分析上限方法的计算公式。讨论了该方法中土体强度、基坑宽度、支护墙体入土深度、基岩埋置深度等因素对坑底抗隆起稳定的影响。通过几个工程的计算与对比,验证了该方法的适用性和优越性。  相似文献   

人工侧向冻结条件下土的冻结试验   总被引：6，自引：2，他引：4  

于琳琳  徐学燕 《岩土力学》2009,30(1):231-235

在人工侧向冻结、正弦和恒温2种冻结温度、开放和封闭条件下,对含水率为32 %的重塑粉质黏土进行了4组冻结试验。结果表明,补水条件相同时侧向正弦冻结试样的冻结速度比封闭正弦冻结试验的缓慢,当其冻结状态进入稳态之后,试样的整体温度场随着侧向冻结温度的正弦变化而出现相应的波动,但径向各段的温度梯度的相位滞后于正弦温度相位半个周期;正弦冻结试样与恒温冻结试样在同一条件下的冻胀量相近,封闭体系下自上而下轴向冻结试样的冻胀量高于同条件下侧向冻结试样的冻胀量;人工冻结工程中应考虑大气环境温度变化（如昼夜温差）及冷能侧向输入土体内时对冻土温度场的变化的影响。  相似文献   

The Verification and Significance of Three Approaches to Longitudinal Stresses in High–resolution Models of Glacier Flow     

Alun Hubbard 《Geografiska Annaler: Series A, Physical Geography》2000,82(4):471-487

With the purpose of improving the ice physics underpinning time–dependent glacier flowline models, three independent approaches for solving longitudinal stresses in glaciers are discussed and verified by application to Haut Glacier d'Arolla. To highlight any shortcomings, the reduced and much utilised driving stress approximation is also applied and compared. Modelled velocity patterns using the three full stress schemes exhibit consistency with one another and good coincidence with observed velocities for the 1991 summer melt season. Furthermore, these stress patterns indicate that longitudinal stresses are significant and of a similar order of magnitude as the basal shear stress components. However, the driving stress approximation yields erratic fluctuations in the stress and velocity fields which are neither realistic in terms of mass continuity nor agree with observations. Basal decoupling experiments indicate a complex relationship between basal velocity and englacial stresses with considerable dampening of any basal perturbation occurring as it is dissipated towards the surface and transferred throughout the ice mass. The driving stress approximation fails to account at all for any such coupling. Experiments to identify the length scale over which longitudinal effects operate indicate that they are significant even up to 10 ice thicknesses. The implication here is that longitudinal stresses play a significant role in determining glacier dynamics on length scales up to at least 2 km and that the predictive power of models of glacier flow based purely on the driving stress approximation is therefore subject to significant limitations. Inclusion of longitudinal stresses overcomes one of the main limitations imposed on such models and, given the potential ease of incorporation of the schemes described here, this deficiency may readily be resolved.  相似文献   

IN SITU MEASUREMENTS OF BASAL WATER QUALITY AND PRESSURE AS AN INDICATOR OF THE CHARACTER OF SUBGLACIAL DRAINAGE SYSTEMS     

DAN B. STONE  GARRY K. C. CLARKE 《水文研究》1996,10(4):615-628

Continuous subglacial measurements of turbidity and electrical conductivity — two indicators of basal water quality — can be used to help characterize subglacial drainage systems. These indicators of water quality yield information that complements that provided by water pressure measurements. Quantitative attributes of subglacial drainage systems, such as water velocity and subglacial residence time, as well as qualitative behaviour — for example, spatial and temporal variations in system morphology — can be deduced using water quality measurements. Interpretation is complicated by the many potential influences on turbidity and electrical conductivity, but when these complications are appreciated a richer interpretation results. To demonstrate the utility of basal water quality measurements, observations from Trapridge Glacier, Yukon Territory, Canada were examined. The data reveal complex behaviour of the drainage system, but constraints imposed by basal water quality measurements help to clarify the nature of the subglacial flow system. The measurement and interpretation methods described and demonstrated are applicable to other glaciers. As such, they should prove useful for characterizing different subglacial drainage configurations and behaviours, thereby improving our general understanding of the hydrology and dynamics of wet-based glaciers.  相似文献