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节理化岩体强度与力学参数估计的地质强度指标GSI法 总被引：2，自引：0，他引：2
确定大体积节理化岩体强度与力学参数是很困难的,这主要是由于节理化岩体试件尺寸太大及岩体所含节理裂隙所致.然而广义HOEK-BROWN准则的出现,为此提供了解决问题的新途径.本文提出了一种确定大体积节理化岩体强度与力学参数的简易经济的新方法——地质强度指标GSI法. 相似文献
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岩体结构面抗剪强度估算方法研究进展 总被引：2，自引：0，他引：2
结构面抗剪强度是工程岩体稳定性评价的重要参数，经验估算方法是获得结构面抗剪强度参数的有效途径之一。随着研究的不断深入，估算方法有可能替代直剪试验直接提供岩体结构面抗剪强度。本文介绍了岩体结构面抗剪强度经验估算方法的研究现状，评述了经验估算方法不同公式的特点，并指出经验估算方法的发展趋势。 相似文献
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Under tension and shear conditions related to unloading of rock mass, a jointed rock mass model of linear elastic fracture mechanics is established. According to the model, the equations of stresses, strains and displacements of the region influenced by the crack but relatively faraway the crack (the distance between the research point and the center of the crack is longer than the length of crack) are derived. They are important for evaluating the deformation of cracked rock. It is demonstrated by the comparison between computational results of these theoretical equations and the observed data from unloading test that they are applicable for actual engineering. 相似文献
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林贤文杨杰臧万军 《福建工程学院学报》2020,(3):228-234
基于正交设计方法,以铁粉、重晶石粉、石英砂为骨料,石膏为胶结剂进行拌和,研究福州某双洞隧道围岩相似材料的极限抗压强度、弹性模量、黏聚力、内摩擦角。 结果表明,不同配比的相似材料其物理力学参数值跨度较广,可以作为大部分岩体的相似材料进行物理模型试验。 通过大量试验,确定相似材料物理力学参数的影响因素并进行敏感性分析,最终确定材料的合理配比,较好地模拟出目标岩体的物理力学参数。 相似文献
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To analyze the stability of a shallow square tunnel, a new curved failure mechanism, representing the mechanical characteristics
and collapsing form of this type of tunnel, is constructed. Based on the upper bound theorem of limit analysis and the Hoek-Brown
nonlinear failure criterion, the supporting pressure derived from the virtual work rate equation is regarded as an objective
function to achieve optimal calculation. By employing variational calculation to optimize the objective function, an upper
bound solution for the supporting pressure and the collapsing block shape of a shallow square tunnel are obtained. To evaluate
the validity of the failure mechanism proposed in this paper, the solutions computed by the curved failure mechanism are compared
with the results calculated by the linear multiple blocks failure mechanism when the Hoek-Brown nonlinear failure criterion
is converted into the Mohr-Coulomb linear criterion. The influences of rock mass parameters on the supporting pressure and
collapsing block shape are discussed. 相似文献
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《天津大学学报(英文版)》2020,(4)
The eff ect of Zn interlayer on the microstructural evolution and mechanical behavior of dissimilar ultrasonic-spot-welded Al/Cu joints was investigated. The tensile lap shear strength in relation to welding energy was analyzed. The experimental results show that two intermetallic compounds, Cu_5Zn_8 and Al_2Cu, were generated at the interface of the ultrasonic-spotwelded Al/Cu joint with a Zn interlayer. The primary joining mechanisms of the joint included the intermetallic compound bonding and metallic bonding caused by solid shear plastic deformation. Meanwhile, with increasing welding energy, the plastic deformation of the material became more substantial. With increasing welding energy, the tensile lap shear strength of the joints fi rst increased and then decreased for the ultrasonic-spot-welded Al/Cu joints with and without Zn interlayers. Under the energy input of 700 J, the bearing load capacity of the ultrasonic-spot-welded Al/Cu joints with a Zn interlayer improved signifi cantly due to the observed intermetallic compound(Cu_5Zn_8). 相似文献
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曾锦秀 《福建工程学院学报》2021,(6):548-544
基于上限法、平面刚架理论与弹性地基梁理论,对双排桩加固边坡中结构变形进行解析,通过数值模拟验证所提方法的合理性,研究了影响双排桩桩身位移的6 个因素。结果表明:当连系梁厚度/ 桩径小于0.7、嵌固段与受荷段长度之比小于0.8、桩径小于1.0 左右时,对桩身位移影响较大,且呈现出明显的非线性特征?桩身弹性模量对双排桩桩身位移同样具有较大影响,但表现出近似线性的特征。对于双排桩加固边坡,可适当增大连系梁厚度、嵌固段长度、桩径、桩身弹性模量或联合注浆改善桩周岩土体的力学性能。研究结果可为边坡中双排桩的设计提供参考。 相似文献
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软硬结构面的存在阻断了岩体性质的连续性,结构面倾角的位置和角度会造成多种破坏模式。文章对上软下硬地层隧道的破坏过程和破坏模式进行数值模拟研究。结果表明:分界结构面倾角在30°～75°时隧道稳定性较差;围岩变形破坏特征在对称模式下,围岩位移、破坏区和塑性区呈对称分布;在非对称模式下,结构面倾角和围岩的力学参数决定了破坏区的位置和范围,破坏区的位置主要受结构面倾角的影响。 相似文献
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Ultrasonic wave testing was applied to investigate the quality and weathering status of rock specimens obtained in two borings
situated in the Xishan Buddha rock slope in Taiyuan, China. This paper pays special attention to the distribution of bulk
density, dynamic parameters and static parameters of rock specimens as well as the relationship between static and dynamic
parameters. The results illustrate that the distribution of both parameters is identical along the depth of two drilled holes
in the rock slope. When the hole depth increases, the density of rock mass, saturated compression strength and static elastic
modulus, dynamic elastic modulus and wave velocity also show increase tendency. The weathering degree in the rock mass ranging
from the surface of cliff to the depth of 2.5 m is the highest while the rock mass is unsalted and more rigid when the depth
is larger than 3.0 m. The relationship between dynamic elastic modulus, sonic wave velocity and horizontal depth indicates
that dynamic elastic modulus is more sensitive than sonic wave velocity. Conversely, by comparing quantity relationship between
static elastic modulus and sonic wave velocity, it is found that the composition of rock has a great influence on the relationship
between static and dynamic parameters, that is, inequality of rock composition will lead to dispersion and abnormality of
the distribution of static and dynamic parameters. 相似文献
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研究目的：分析深埋隧道的塌方机制并推导塌方体形状曲线的解析表达式。创新要点：基于霍克-布朗准则,采用泛函突变理论推导得到了深埋隧道塌方体形状曲线的解析表达式,并据此分析了围岩参数变化对塌方体形状的影响规律。研究方法：通过理论分析建立深埋圆形隧道的解析模型（图1）,采用泛函突变理论推导基于霍克-布朗准则的隧道塌方体形状曲线解析表达式,并研究围岩参数变化对塌方体形状的影响规律（图3和4,表2）。通过与自然拱理论和模型试验结果的对比（图5–7）验证本文解析解的正确性。重要结论：采用泛函突变理论推导了基于霍克-布朗准则的深埋隧道塌方体形状曲线解析表达式。该解析表达式简洁直观,不仅可以预测无支护条件下隧道的塌落体尺寸,还可以估算塌落围岩作用于衬砌上的荷载。 相似文献
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JRC-JCS模型在抗剪强度参数取值中的应用 总被引：3，自引：0，他引：3
工程岩体的失稳几乎都是沿着结构面发生的。而岩体结构面的抗剪性质并不完全满足莫尔一库仑准则，因此在岩质边坡的稳定性分析中采用莫尔一库仑准则有可能会带来较大误差。本文简要的回顾了岩体结构面抗剪强度估算方法发展的历程，提出了基于JRC-Jcs模型计算等效抗剪强度参数的概念和方法，并通过简单计算实例阐明了这一方法在处理实际工程问题中的特点。 相似文献
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The characteristics of microstructure, mechanical property and corrosion behavior of Cr26Mo3.5 super stainless steel joints by pulse tungsten inert gas(P-TIG)welding and laser welding were investigated. The results indicate that the widths of the center equiaxed grain zone(EGZ)and the columnar grain zone(CGZ)increase with the increase of heat input in both welding processes. The precipitates of Nb and Ti carbides and nitrides are formed in the weld metal(WM)and the heat affected zone(HAZ). The joints by laser welding show better tensile and corrosion resistance properties than those by P-TIG welding due to the heat concentration and lower heat input. The tensile strength and elongation increase with the decrease of heat input, and the fracture mode of the joints turns into ductile-brittle mixed fracture from ductile fracture when the welding method turns into P-TIG welding from laser welding. Moreover, the corrosion resistance of all joints declines slightly with the increase of heat input. Hence, laser welding is more suitable for welding Cr26Mo3.5 super stainless steel in engineering applications. 相似文献
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刘如月薛潘荣颜桂云 《福建工程学院学报》2020,(6):553-559
为实现装配式结构震损后能快速修复以恢复使用功能,提出一种带可恢复功能节点的装配式框架结构体系。利用ABAQUS 有限元软件对可恢复功能节点进行数值模拟,探讨可恢复功能节点的作用机理,并将可恢复功能节点布置到装配式框架结构中形成可恢复功能装配式框架结构,考察整体结构的受力机理,可更换耗能铰、装配式节点核心区与梁柱部件的失效演化规律。结果表明,节点的失效主要是由于可恢复功能节点在削弱钢板处的损伤累积引起的断裂导致?与现浇混凝土框架及节点加强型现浇混凝土框架相比,可恢复功能装配式框架的承载能力更高、延性更好,通过可更换耗能铰的塑性变形耗散能量大幅度提高了结构的耗能能力,且结构的损伤破坏集中在削弱钢板上,有效地避免了预制梁柱和节点核心区的损伤。震后通过更换损伤耗能元件即可恢复结构的使用功能,实现了损伤可控和震后功能可恢复的抗震设防理念,具有广泛的应用前景。 相似文献
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为了分析不同倾角结构面对裂隙岩体强度及变形性质的影响,本文通过数值模拟的方法,分析了0°、15°、30°、45°、60°、75°、90°7种典型倾角结构面岩体在三轴压缩条件下的应力应变响应,并从微观角度分析了结构面的变形性质.研究结果表明：在相同围压条件下,随着结构面倾角的增大,不同倾角结构面岩石试件抗压强度呈先减小后增大趋势;含有90°倾角结构面的岩石试件的抗压强度与含有0°倾角结构面岩石试件的相等;随着结构面倾角的增大,结构面上的剪应力的变化趋势是由中部向结构面倾向方向的两侧扩展,并且逐渐趋于集中. 相似文献
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Pascal PERROTIN 《天津大学学报(英文版)》2006,12(Z1)
A new concept of structurally dissipating rock-shed (SDR) was developed by the lab of Tonello IC and LOCIE-ESIGEC (France). To decide the dimension of the plate used in SDR, an ANSYS model which could simulate the impact of rock in the centre of the plate was established by Fabien Delhomme. By using this model, some finite element analyses are carried out in the present paper. Firstly, a plate impacted by a block is numerically simulated, the numerical results obtained from different mesh sizes are compared and the accuracy of the finite element model is verified. Then, the dynamic response of the plate impacted at the boundary and in the medium part is computed. By analyzing the stress in rebar, the most dangerous region of impact of plate was found. For a rectangular plate, the most dangerous region is at the corner of the plate when a block drops in. Finally, the whole deformation process of the plate under dropping block was simulated and a simplified definition (effect zone) to describe the deformation process in different positions of plate was given. From this study, it is found that the impact only affects heavily within the effect zone. 相似文献
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采用三维数值方法,建立长短桩、变径桩双桩模型,通过大量的数值计算,分析桩顶荷载水平、桩距径比、不同桩长、桩端土模量比及不同桩径对相互作用系数的影响。分析表明,在线弹性变形阶段,桩-桩相互作用系数近似为恒定值,与桩顶荷载水平无关,进入塑性变形之后,则逐渐减小直至极限状态时趋于0;长短桩桩长比及桩端土模量比对短桩-长桩相互作用系数影响大,而对长桩-短桩相互作用系数影响小;变径桩相互作用系数仅与受荷桩桩径有关;并提出了针对长短桩、变径桩的简化计算公式,为实际工程提供参考。 相似文献