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31.
为探究冻融循环对节理岩石抗剪力学特性的影响,针对冻融循环前后不同连通率节理岩石试样进行剪切特性试验,探究了节理试样的剪切破坏机制,对比分析了冻融前后节理试样抗剪强度的衰减趋势,分析了黏聚力及内摩擦角随岩石试样剪切破坏面分形维数的变化规律。结果表明:随冻融循环次数的增加,节理试样剪切应力-位移曲线发生显著变化,峰值剪应力出现明显下降,黏聚力及内摩擦角对比冻融前试样出现明显劣化,并且随节理试样连通率的增加,劣化程度加剧;在节理连通率相同时,随冻融循环次数的增加,剪切破坏面的分形维数呈现近指数函数递增的趋势,随分形维数的增加,节理试样的黏聚力损伤因子、内摩擦损伤因子也呈现指数函数增加的趋势;在冻融循环次数相同时,内摩擦角损伤因子随节理连通率的增大呈先减小后增大的趋势,而黏聚力损伤因子在冻融循环次数为30次前后分别呈递增和先减后增的趋势。 相似文献
32.
33.
Dov Bahat 《Rock Mechanics and Rock Engineering》1988,21(1):79-94
Summary Measurements of fracture joint distribution combined with determinations of plume length and orientation on a vertical section of a single chalk layer near Beer Sheva, Israel, reveal that joints marked by unilateral and circular plumes are skewed towards the shorter sizes while joints decorated by bilateral plumes are skewed towards the longer sizes. The mean lengths of the unilateral and bilateral joints are 66.5 cm and 155.6 cm, with standard deviations of 30 cm and 60.6 cm, respectively. These results as well as joint length observations from other areas seem to suggest a bimodal length distribution. However, since the minor maximum is generally very weak, and due to some additional uncertainties, further confirmation of the present observations is needed. 相似文献
34.
Xing Zhang 《Geotechnical and Geological Engineering》1993,11(2):107-124
Summary Based on an extension to a model originally proposed by Zhang (1990), a method for estimating the shear strength of a jointed rock mass containing two joint sets is developed. Compared to the original method in which only a single en-echelon joint set was considered, the new method has the following advantages: (1) it allows a much more realistic joint pattern to be incorporated; (2) the effects of joint connectivity and intersection angle between joint sets on shear strength are included. Use of the new method is demonstrated by application to the calculation of the stability of slopes in jointed rock. The importance of joint connectivity, joint persistence and joint set intersection angle on slope stability, as predicted by the model, is revealed. 相似文献
35.
Xian-Kang Zhang Zhuo-Xin Yang Yu-Chun Yang Jian Yang Jian-Li Song Ping Zhao 《地震学报(英文版)》1995,8(4):519-529
In this paper, the theory and method, obtaining the tomographic determination of three-dimensional velocity structure of the
crust by use of the joint inversion of explosion and earthquake data, are given. The velocity distribution of the crust is
regarded as a continuous function of the spatial coordinates without parametrization of the velocity model ahead, so that
the inversion solution would not be influenced by different parametrization procedures. The expressions of integration kernels,
which relates the two kinds of data sets, are also given. The authors have processed the observed data in Tangshan earthquake
region by the method proposed in this paper, and obtained the tomographic results of the middle and upper crust structures
in this region. The comparison of these results with the result obtained only by the explosion data, has also been made. 相似文献
36.
Centrifuge Modeling of Rock Slopes Susceptible to Block Toppling 总被引:2,自引:0,他引:2
Summary This paper presents the results of centrifuge tests that were aimed at validating the Goodman-Bray method for rock slope toppling
analysis. The Goodman-Bray method was extended by the authors to accommodate non-persistent basal planes of rock columns.
Two gypsum column models, with and without anchors were used to represent the failure modes. Measured critical centrifuge
accelerations were in agreement with the results obtained from numerical modeling. A background of the toppling slope failures
associated with a large hydropower project in China instigated the need for the centrifuge study. The centrifuge model tests
used an artificial rock. The observed failure mode did not follow a straight failure plane as proposed by Goodman and Bray.
The failures revealed a bi-planar slip surface with a deep-seated portion near the toe of the slope. The outcomes of the centrifuge
tests illustrated the need to search for the critical failure surface when performing a toppling analysis. The search technique
is similar to that usually performed in a conventional sliding analysis. 相似文献
37.
Sara Casciati 《地震工程与工程振动(英文版)》2007,6(3):259-268
The joints connecting vertical and horizontal elements are the "weak link" in structural systems assembled from wood panels. If they are too weak, local failures may occur, resulting in performance that is significantly below expectations. If they are too resistant, the joints may be unable to dissipate energy during vibrations, thus possibly initiating a fast progressive failure. This paper re-processes and re-elaborates the results of shaking table tests previously carried out by the author and other co-workers. The goal is to assess the feasibility of a joint which is able to dissipate energy during vibration, without degrading the connection performance. 相似文献
38.
A time-domain method for the analysis of arch dam-foundation rock dynamic interaction during earthquake was proposed, and
the dynamic relaxation technique was adopted to obtain the initial static response for dynamic analysis by [Du et al. (2005).
The paper has been contributed to Bulletin of earthquake engineering]. In this paper, a nonlinear explicit method in time
domain considering the opening and closing effect of contact joints on arch dam during earthquake is further proposed by introducing
the dynamic contact force model into the method. The simulation accuracy of dynamic contact force model is verified by comparing
its calculation result and test result of scale model on shaking table. Finally, the influence of joints on the seismic response
of Xiaowan arch dam is studied by the proposed method and some conclusions are given. 相似文献
39.
40.
和龙岩体赋存于新太古代夹皮沟—金城洞花岗绿岩带中,与围岩发生同变形变质。岩体具有典型的科马提岩冷凝结构分层和鬣刺结构、冷凝多面体节理。上述特征是作者1990年发现确认的。该科马提岩的矿物学特征:玻璃质脱玻形成铁皂石等矿物;斜方辉石和橄榄石鬣刺呈中空骸晶状,大部被滑石、铁白云石、绿泥石、磁铁矿等取代,但仍保留完好的长柱状假像;堆积带中橄榄石呈微细粒、新鲜,仅发生网状蛇纹石化。岩石化学特征富MgO,CaO/Al_2O_3=1.04,用科马提岩分类图判别为超镁铁质科马提岩。 相似文献