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1.
High temperature damage of rock is a critical problem that must be well known for underground coal gasification, underground storage of nuclear waste, repairment of underground buildings after fire disaster. In order to study the influences of loading rate and high temperature on the tensile strength of sandstone, Brazilian splitting tests were conducted on sandstone disk samples treated with five different temperature levels between 25 and 800 °C at six different loading rates between 0.01 and 10 mm/min. Test results showed that tensile strength of disk samples increases gradually and reaches to the maximum at the temperature level of 400 °C, then drop sharply. The tensile strength of sandstone samples is characterized by obvious rate effect and it increases continuously with the increase of loading rate, meeting a Logarithmic Function. The lower limit tensile strength of sandstone ignoring the influence of rate effect was calculated, and it is helpful for providing some basis for the design of rock engineering.  相似文献   

2.

To study the tensile strength of rock under different loading rates, direct tensile test is the most accurate method. However, the eccentric tension in the process of rock direct tensile test has a significant influence on the test results. In this paper, firstly, a self-developed centering device for rock direct tensile test is introduced, which can effectively eliminate the eccentric tension in the process of rock direct tensile test. Then, with the aid of the self-developed centering device, the direct tensile tests of red sandstone under the loading rates of 0.001 mm/s, 0.01 mm/s and 0.1 mm/s are successfully carried out. After tests, both the macro failure characteristics and the scanning electron microscope micrograph show that the fracture pattern of the rock is caused by pure tensile loading. The stress-strain curves of the direct tensile test of the red sandstone show that the process of the direct tensile test can be roughly divided into four stages. With the increase of loading rate, both of the tensile strength and the peak tensile strain of the rock increase obviously. The direct tensile test of the red sandstone shows obvious loading rate effect.

  相似文献   

3.
Arc fissure is one of the basic forms of defective rock, where the expansion and evolution mechanism plays an important role in the stability of engineering rock mass under the external load action. Uniaxial compression experiments of sandstone samples that contained various angles of arc fissures (sandstone sample was 80 mm?×?160 mm?×?30 mm) were performed in order to investigate the effect that arc angle α had on the mechanical properties, the failure mode, and the fracture evolution process of sandstone. The results showed that when arc angle α was increased, the peak strength and the strain of the sandstone samples initially decreased before increasing and the minimum peak strength and strain were reached when α?=?15°. The deterioration of the bearing capacity and the number of cracks that appeared during the sandstone loading process decreased as the arc angle of the fissure increased. The arc fissure destruction was primarily initiated from the fragile area of the arch tip. The tensile cracks appeared on the fissure tip and non-tip as the axial force increased. The various arc angle α played an important role in the initiation stress and the rupture evolution of the specimen.  相似文献   

4.
To analyse the fracture coalescence behaviour of rock, rectangular prismatic sandstone specimens (80?×?160?×?30?mm in size) containing three fissures were tested under uniaxial compression. The strength and deformation behaviours of the specimens are first analysed by investigating the effects of the ligament angle β2 on the peak strength, peak strain and crack initiation stress of the specimens. To confirm the sequence of crack coalescence, a photographic monitoring technique is used throughout the entire period of deformation. Based on the results, the relationship between the real-time crack coalescence process and the axial stress–strain curve of brittle sandstone specimens is also developed, and this relationship can be used to evaluate the macroscopic deformation characteristics of pre-cracked rock. The equivalent strain evolution fields of the specimen, with α?=?β1?=?45° and β2?=?90°, are obtained using the digital image correlation technique and show good agreement with the experimental results of pre-cracked brittle sandstone. These experimental results are expected to improve the understanding of fracture mechanisms and be used in rock engineering with intermittent structures, such as deep underground excavated tunnels.  相似文献   

5.
地下洞室开挖爆破围岩松动圈的数值分析计算   总被引：4，自引：2，他引：2  
肖明  张雨霆  陈俊涛  田华 《岩土力学》2010,31(8):2613-2618
根据数值计算提出了在地下洞室开挖爆破中,确定围岩松动圈的方法。给出了地下洞室开挖爆破的三维弹塑性损伤有限元计算方法。该方法论述了爆破荷载、重力荷载和开挖荷载的计算、施加以及迭代的方法,可以合理反应爆破对围岩稳定的影响和锚固支护施加的效果;结合岩石松动圈的实测方法,推导了判定围岩开始松动的损伤系数阈值公式,可以结合数值计算得到的洞周围岩损伤系数分布,确定在开挖爆破作用下围岩松动圈的范围。对实际工程的分析计算表明,根据数值计算判定的围岩松动范围与实测松动范围的规律基本一致,量值吻合较好,其结果为地下洞室开挖爆破的围岩松动圈的确定提供了有效的方法。  相似文献   

6.
Size and strain rate are two key factors that dramatically influence the estimation of rock mechanical behaviors. To better understand the effects of size and strain rate on measured rocks, rock specimens with six different sizes were tested at six different strain rates under uniaxial compression using the MTS 815 Rock Mechanics Test System. Having determined that the size and strain rate significantly affect the peak strain, peak stress, elastic modulus, acoustic emission (AE), and failure pattern of the rock specimens, the relation was established between the strength and the size and strain rate of red sandstone. And the variation was revealed among the size and strain rate, the AE, and the failure pattern. It turned out that the peak stress was negatively correlated with the rock size and was positively correlated with the strain rate. When the length to diameter ratio (L/D) of the rock specimen was less than 2.0, the AE appeared mildly. The AE quantities gradually increased before the peak stress, and then sharply decreased after the peak stress. The failure pattern of the rock specimen was relatively complicated, with a fracture plane appearing along the axial direction. Conical failure type was also presented. When the L/D ratio of the specimen was greater than 2.0, the AE characteristics of red sandstone showed the radical model. There were relatively few AE rings before the peak stress. But the AE rings increased suddenly and dramatically during the peak stress. The rock specimens primarily failed with a single shear plane. Moreover, with an increase in the strain rate, the AE activities were enhanced and the AE quantities increased. When the strain rate of the rock specimen was less than 5.0?×?10?4/s, the rock specimen failed with a shear or tensile-shear pattern. And when the strain rate was greater than 5.0?×?10?4/s, the rock specimen tended to fail in a conical pattern.  相似文献   

7.
Three different types of permeability tests were conducted on 23 intact and singly jointed rock specimens, which were cored from rock blocks collected from a rock cavern under construction in Singapore. The studied rock types belong to inter-bedded meta-sandstone and meta-siltstone with very low porosity and high uniaxial compressive strength. The transient pulse water flow method was employed to measure the permeability of intact meta-sandstone under a confining pressure up to 30 MPa. It showed that the magnitude order of meta-sandstone’s intrinsic permeability is about 10?18 m2. The steady-state gas flow method was used to measure the permeability of both intact meta-siltstone and meta-sandstone in a triaxial cell under different confining pressures spanning from 2.5 to 10 MPa. The measured permeability of both rock types ranged from 10?21 to 10?20 m2. The influence of a single natural joint on the permeability of both rock types was studied by using the steady-state water flow method under different confining pressures spanning from 1.25 to 5.0 MPa, including loading and unloading phases. The measured permeability of both jointed rocks ranged from 10?13 to 10?11 m2, where the permeability of jointed meta-siltstone was usually slightly lower than that of jointed meta-sandstone. The permeability of jointed rocks decreases with increasing confining pressure, which can be well fitted by an empirical power law relationship between the permeability and confining pressure or effective pressure. The permeability of partly open cracked specimens is lower than that of open cracked specimens, but it is higher than that of the specimen with a dominant vein for the meta-sandstone under the same confining pressure. The permeability of open cracked rock specimens will partially recover during the unloading confining pressure process. The equivalent crack (joint) aperture is as narrow as a magnitude order of 10?6 m (1 μm) in the rock specimens under confining pressures spanning from 1.25 to 5.0 MPa, which represent the typical ground stress conditions in the cavern. The in situ hydraulic conductivity measurements conducted in six boreholes by the injection test showed that the in situ permeability of rock mass varies between 10?18 and 10?11 m2. The lower bound of the in situ permeability is larger than that of the present laboratory-tested intact rock specimens, while the upper bound of the in situ permeability is less than that of the present laboratory-tested jointed rock specimens. The in situ permeability test results were thus compatible with our present laboratory permeability results of both intact and jointed rock specimens.  相似文献   

8.
Based on the damage mechanism of rock during excavation, the maximum tensile strain criterion for pinpointing relaxation region or excavation‐disturbed (damage) zone (EDZ) is introduced. To simulate the deformation and stress redistribution caused by the deterioration of the deformation and strength parameters in the EDZ, the ‘restraint‐relaxation’ finite element algorithm is formulated using the deformation and strength parameters of pre‐and post‐relaxation. The Xiaowan arch dam project (292 m high) is studied by the proposed method, in which the permissible tensile strain and fluidity parameter are evaluated using back analysis. The computation results have good agreement with the field monitoring. An important inference from the study is the necessity of considering the relaxation effects on the dam/foundation system during the construction and operation period. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

9.
As technologies for deep underground development such as tunneling underneath mountains or mass mining at great depths (>1,000 m) are implemented, more difficult ground conditions in highly stressed environments are encountered. Moreover, the anticipated stress level at these depths easily exceeds the loading capacity of laboratory testing, so it is difficult to properly characterize what the rock behavior would be under high confinement stress conditions. If rock is expected to fail in a brittle manner, behavior changes associated with the relatively low tensile strength, such as transition from splitting to the shear failure, have to be considered and reflected in the adopted failure criteria. Rock failure in tension takes place at low confinement around excavations due to tensile or extensional failure in heterogeneous rocks. The prospect of tensile-dominant brittle failure diminishes as the confinement increases away from the excavation boundary. Therefore, it must be expected that the transition in the failure mechanism, from tensile to shear, occurs as the confinement level increases and conditions for extensional failure are prevented or strongly diminished. However, conventional failure criteria implicitly consider only the shear failure mechanism (i.e., failure envelopes touching Mohr stress circles), and thus, do not explicitly capture the transition of failure modes from tensile to shear associated with confinement change. This paper examines the methodologies for intact rock strength determination as the basic input data for engineering design of deep excavations. It is demonstrated that published laboratory test data can be reinterpreted and better characterized using an s-shaped failure criterion highlighting the transition of failure modes in brittle failing rock. As a consequence of the bi-modal nature of the failure envelope, intact rock strength data are often misinterpreted. If the intact rock strength is estimated by standard procedures from unconfined compression tests (UCS) alone, the confined strength may be underestimated by as much as 50 % (on average). If triaxial data with a limited confinement range (e.g., σ3 ? 0.5 UCS due to cell pressure limitations) are used, the confined strength may be overestimated. Therefore, the application of standard data fitting procedures, without consideration of confinement-dependent failure mechanisms, may lead to erroneous intact rock strength parameters when applied to brittle rocks, and consequently, by extrapolation, to correspondingly erroneous rock mass strength parameters. It follows that the strength characteristics of massive rock differ significantly in the direct vicinity of excavation from that which is remote with higher confinement. Therefore, it is recommended to adopt a differentiated approach to obtain intact rock strength parameters for engineering problems at lower confinement (near excavation; e.g., excavation stability assessment or support design), and at elevated confinement (typically, when the confinement exceeds about 10 % of the UCS) as might be encountered in wide pillar cores.  相似文献   

10.
ABSTRACT

In this study, over 1000 data from the literature was used to characterize and compare the density, strengths, modulus, fracture toughness, porosity and the ultimate shear strengths of the gypsum, limestone and sandstone rocks. The compressive modulus and Mode-1 fracture toughness of the gypsum rock, limestone rock and sandstone rocks varied from 0.7 GPa to 70 GPa, and from 0.03 MPa.m0.5 to 2.6 MPa.m0.5  respectively. Vipulanandan correlation model was effective in relating the modulus of elasticity, fracture toughness with the relevant strengths of the rocks. A new nonlinear Vipulanandan failure criterion was developed to quantify the tensile strength, pure shear (cohesion) strength and to predict the maximum shear strength limit with applied normal stress on the gypsum, limestone and sandstone rocks. The Vipulanandan failure model predicts the maximum shear strength limit was, as the Mohr-Coulomb failure model does not have a limit on the maximum shear strength. With the Vipulanandan failure model based on the available data, the maximum shear strengths predicted for the gypsum, limestone and sandstone rocks were 64 MPa, 114 MPa and 410 MPa respectively.  相似文献   

11.
Strain rate during testing, uniaxial or triaxial, has important influence on the measured mechanical properties of rocks. Uniaxial compression tests were performed at nine pre-specified static-to-quasistatic strain rates (ranging from 1 × 10?5 to 1 × 10?1 s?1) on coarse crystal marble. The aim is to gain deep insight into the influence of strain rate on characteristic stresses, deformation properties and conversion of strain energy of such rock. It is found that the strain rate of 5 × 10?3 s?1 is the threshold to delineate the failure modes the tested coarse marble behaves in. At a strain rate less than this threshold, single-plane shear and conjugate X-shaped shear are the main failure modes, while beyond this threshold, extensile and splitting failures are dominant. The stress for crack initiation, the critical stress for dilation, the peak stress, and Young’s modulus are all found to increase with strain rate, with an exception that the above stresses and modulus appear relatively low compared to the strain rate in the range of between 1 × 10?4 and 5 × 10?3 s?1. The pre-peak absorbed strain energy, damage strain energy and elastic strain energy are found to increase with strain rate. In addition, the elastic strain energy stored before peak point favors brittle failure of the specimen, as the more stored elastic energy in the specimen, the stronger the fragmenting.  相似文献   

12.
Weathering of rocks that regulate the water chemistry of the river has been used to evaluate the CO2 consumption rate which exerts a strong influence on the global climate. The foremost objective of the present research is to estimate the chemical weathering rate (CWR) of the continental water in the entire stretch of Brahmaputra River from upstream to downstream and their associated CO2 consumption rate. To establish the link between the rapid chemical weathering and thereby enhance CO2 drawdown from the atmosphere, the major ion composition of the Brahmaputra River that drains the Himalaya has been obtained. Major ion chemistry of the Brahmaputra River was resolved on samples collected from nine locations in pre-monsoon, monsoon and post-monsoon seasons for two cycles: cycle I (2011–2012) and cycle II (2013–2014). The physico-chemical parameters of water samples were analysed by employing standard methods. The Brahmaputra River was characterized by alkalinity, high concentration of Ca2+ and HCO3 ? along with significant temporal variation in major ion composition. In general, it was found that water chemistry of the river was mainly controlled by rock weathering with minor contributions from atmospheric and anthropogenic sources. The effective CO2 pressure (log\({{\text{P}}_{{\text{C}}{{\text{O}}_{\text{2}}}}}\)) for pre-monsoon, monsoon and post-monsoon has been estimated. The question of rates of chemical weathering (carbonate and silicate) was addressed by using TDS and run-off (mm year?1). It has been found that the extent of CWR is directly dependent on the CO2 consumption rate which may be further evaluated from the perspective of climate change mitigation The average annual CO2 consumption rate of the Brahmaputra River due to silicate and carbonate weathering was found to be 0.52 (×106 mol Km?2 year?1) and 0.55 (×106 mol Km?2 year?1) for cycle I and 0.49 (×106 mol Km?2 year?1) and 0.52 (×106 mol Km?2 year?1) for cycle II, respectively, which were significantly higher than that of other Himalayan rivers. Estimation of CWR of the Brahmaputra River indicates that carbonate weathering largely dominates the water chemistry of the Brahmaputra River.  相似文献   

13.
It is well-known that the strengths of sandstones measured under fully saturated conditions are smaller than those measured under nominally dry conditions. This strength softening phenomenon has profound implications to rock engineering. In this work we investigate the tensile strength softening of Longyou sandstone from China. Defining the strength softening factor as the ratio of the strength under nominally dry conditions over that under saturated conditions, the static compressive strength softening factor of Longyou sandstone is close to 2 and the static tensile strength softening factor is about 7.9. To further address the applications, where the load may be dynamic, we examine the rate dependence of the tensile strength softening of this sandstone. The dynamic tensile strength is measured using the split Hopkinson pressure bar system in combination with the Brazilian disc sample geometry. The results show that the tensile strength softening factor decreases with the loading rate. Because the saturated sample shows stronger loading rate sensitivity than the dry sample, the softening factor decreases with the loading rate.  相似文献   

14.
The radioactivity due to 238U and 234U in three aquifer systems occurring within the Paraná sedimentary basin, South America, has been investigated. Uranium is much less dissolved from fractured igneous rocks than from the porous sedimentary rocks as indicated by the U-mobility coefficients between 7.6 × 10?6 and 1.2 × 10?3 g cm?3. These values are also compatible with the U preference ratios relative to Na, K, Ca, Mg and SiO2, which showed that U is never preferentially mobilized in the liquid phase during the flow occurring in cracks, fissures, fractures and faults of the igneous basaltic rocks. Experimental dissolution of diabase grains on a time-scale laboratory has demonstrated that the U dissolution appeared to be a two-stage process characterized by linear and second-order kinetics. The U dissolution rate was 8 × 10?16 mol m?2 s?1 that is within the range of 4 × 10?16–3 × 10?14 mol m?2 s?1 estimated for other rock types. The 234U/238U activity ratio of dissolved U in solutions was higher than unity, a typical result expected during the water–rock interactions when preferential 234U-leach from the rock surfaces takes place. Some U-isotopes data allowed estimating 320 ka for the groundwater residence time in a sector of a transect in São Paulo State. A modeling has been also realized considering all U-isotopes data obtained in Bauru (35 samples), Serra Geral (16 samples) and Guarani (29 samples) aquifers. The results indicated that the Bauru aquifer waters may result from the admixture of waters from Guarani (1.5 %) and Serra Geral (98.5 %) aquifers.  相似文献   

15.
Theoretical Concept to Understand Plan and Design Smooth Blasting Pattern   总被引：1，自引：0，他引：1  
Considering different mechanical cutting tools for excavation of rock, drilling and blasting is said to be inexpensive and at the same time most acceptable and compatible to any geo-excavation condition. Depending upon strength properties of in-situ rock mass, characteristics of joint pattern and required quality of blasting, control blasting techniques viz., pre-split and smooth blasting are commonly implemented to achieve an undamaged periphery rock-wall. To minimize magnitude of damage or overbreak, the paper emphasized that in-situ stresses and re-distribution of stresses during the process of excavation should be considered prior to selection of explosive parameters and implementation of any suitable blast pattern. Rock structure being not massive in nature, the paper firstly explains the influence of discontinuities and design parameters on smooth-wall blasting. Considering the empirical equations for estimation of stress wave’s magnitude and its attenuation characteristics through transmitting medium, the paper has put forward a mathematical model for smooth blasting pattern. The model firstly illustrates that rock burden for each hole should be sub-divided into thin micro strips/slabs to understand the characteristics of wave transmission through the medium and lastly with the help of beam theory of structural dynamics have put forward a mathematical model to analyze and design an effective smooth blasting pattern to achieve an undamaged periphery rock-wall.  相似文献   

16.
刘会波  肖明  张志国  陈俊涛 《岩土力学》2012,33(7):2133-2141
将地下洞室爆破开挖松动区视为一个随开挖过程演变的非均匀、非稳定三维扰动场,松动区内岩体力学参数则是一个具有时空演化特性的参数场。考虑爆破开挖扰动空间效应和岩体真实变形响应,提出了真实工作状态下开挖松动区岩体参数场辨识的位移反分析方法。基于局部监测变形空间插补得到的空间位移场,通过分析洞室爆破开挖围岩变形扰动机制,建立了开挖松动区岩体变形模量参数场数值演化模型,并进行了模型适用性和参数敏感性分析。在此基础上,以变形模量参数为例,结合围岩实测位移信息,提出了开挖松动区参数场位移反分析的动态实现过程。将该方法应用于溪洛渡地下洞室群施工期参数场反演和围岩稳定动态反馈评价及预测,结果表明,该方法合理有效,在大型地下洞群施工开挖与快速监测反馈方面具有显著的工程适用性及实用性。  相似文献   

17.
硬脆性围岩在开挖完成后，其强度在高应力的影响下具有明显的时间效应，这导致围岩开挖损伤区的发展也呈现出与时间相关的特征。在岩石强度时效性演化模型的基础上，以锦屏二级水电站试验洞钻孔摄像、声波、变形监测等开挖损伤区实测结果为目标函数，采用正交设计方法、最小二乘支持向量机模型、粒子群优化算法等方法，建立了考虑时间效应的LSSVM-PSO智能反演分析方法，并以锦屏二级水电站试验洞为例，研究了开挖完成后的25 d里，围岩强度在高地应力条件下的时效性演化特征，进而获得这一时段内开挖损伤区扩展过程。研究结果表明：（1）高应力地区，隧洞开挖后，围岩损伤区的主要扩展方向受地应力控制，且最大扩展方向为最小主应力方向，且破坏区（破坏接近度FAI≥2）也集中于该方向； （2）开挖损伤区面积随时间近似呈S形曲线变化，表明开挖损伤区初始发展较为缓慢，随着时间推移呈现线性增加的趋势，最后又逐渐趋于稳定；（3）开挖后第3～10 d为开挖损伤区快速增长阶段。该研究成果对高应力地区硬脆性围岩开挖损伤区时效性演化研究具有指导意义。  相似文献   

18.
Quantifying rock fall hazards requires information about their frequency and volumes. Previous studies have focused on quantifying rock fall volume–frequency relationships or the weather conditions antecedent to rock fall occurrences, and their potential use as prediction tools. This paper is focused on quantifying rock fall occurrence probabilities and presents approaches for quantifying rock fall temporal distributions. In particular, von Mises distributions allow direct correlation between seasonal weather variations and rock fall occurrences. The approaches are illustrated using a rock fall database along a railway corridor in the Canadian Cordillera, in which rock fall occurrences were correlated to the morphology and lithology. A Binomial probability distribution applied to the annual rock fall frequency suggests an average daily rock fall probability of 1 × 10?2 across the study area. However, circular (von Mises) distributions associated with weather trends in the area, and fitted to monthly rock fall records, allow estimation of daily rock fall probabilities in different months. This approach allows a direct correlation between rock fall frequencies and seasonal variations in weather conditions. The results suggest daily rock fall probabilities between 4 × 10?3 and 8 × 10?3 for April through July and up to 2.1 × 10?2 in October. Moreover, local peaks in rock fall monthly records are quantitatively explained through the seasonality of weather conditions. Similar values are obtained when applying the Binomial distribution to monthly records. However, this last approach does not show strong distribution fits and does not allow a correlation between rock fall frequencies and seasonal weather variations.  相似文献   

19.
A hydrogeological study was conducted in Potsdam sandstones on the international border between Canada (Quebec) and the USA (New York). Two sandstone formations, arkose and conglomerate (base) and well-cemented quartz arenite (upper), underlie the study area and form the major regional aquifer unit. Glacial till, littoral sand and gravel, and marine silt and clay discontinuously overlie the aquifer. In both sandstone formations, sub-horizontal bedding planes are ubiquitous and display significant hydraulic conductivities that are orders of magnitude more permeable than the intact rock matrix. Aquifer tests demonstrate that the two formations have similar bulk hydrologic properties, with average hydraulic conductivities ranging from 2?×?10?5 to 4?×?10?5 m/s. However, due to their different lithologic and structural characteristics, these two sandstones impose rather different controls on groundwater flow patterns in the study area. Flow is sustained through two types of fracture networks: sub-horizontal, laterally extensive fractures in the basal sandstone, where hydraulic connectivity is very good horizontally but very poor vertically and each of the water-bearing bedding planes can be considered as a separate planar two-dimensional aquifer unit; and the more fractured and vertically jointed system found in the upper sandstone that promotes a more dispersed, three-dimensional movement of groundwater.  相似文献   

20.
为研究加载速率对砂岩抗拉强度的影响效应及影响机制,设计开展5种加载速率的劈裂试验,综合分析抗拉强度、破坏特征、能量参数和劈裂面微观形貌变化规律及相关性。结果表明,(1) 随着加载速率增大,砂岩劈裂抗拉强度逐渐增大,总体呈现先陡后缓的趋势,加载速率在0.01～0.10 kN/s范围内时抗拉强度增长迅速,0.10～1.00 kN/s范围内时抗拉强度增长趋势渐缓;(2) 随着加载速率的增大,岩样吸收的总能量增大,弹性应变能占总能量的比值逐渐增大,耗散能占总能量的比值逐渐减小,加载至破坏时裂纹扩展形成宏观劈裂面的时间呈数量级减小,达到峰值应力时弹性应变能的释放,导致岩样破坏的突发性增强,使得劈裂面形貌特征在宏观和微观上逐渐变得复杂,对应抗拉强度逐渐增大;(3) 在岩石劈裂试验过程中加载速率、能量参数、劈裂面形貌特征与抗拉强度密切相关,加载速率影响加载过程中能量的总量与分配,能量参数的变化直接影响岩样的破坏过程及劈裂面的形貌特征,最后宏观上表现为抗拉强度的差异。文中相关分析方法和思路可为类似试验提供较好的参考。  相似文献   

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