共查询到19条相似文献，搜索用时 231 毫秒
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应力波理论在动测锚杆锚固质量中的应用 总被引：11，自引：0，他引：11
运用应力波理论，分析了不同锚固质量的锚杆在瞬态冲击下的响应规律，包括锚固质量优的、中等的、劣的对锚杆中应力波的影响规律。这些规律都将会对实际锚杆锚固质量的无损检测起到很好的指导作用。 相似文献
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针对高压摆喷防渗墙目前检测存在的问题,本文介绍了弹性波CT技术检测的基本原理和过程,对某水库大坝高压摆喷防渗墙的质量进行检测,并对部分墙体进行钻孔取芯及注水试验验证,通过实例分析,结果表明弹性波CT技术在防渗墙质量检测中具有检测速度快,检测准确度高的优点,在防渗墙质量无损检测中具有广阔的应用前景。 相似文献
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预应力锚杆(索)框架梁加固边坡的仿真试验分析 总被引：1，自引：0，他引：1
采用数值仿真试验方法研究了预应力锚杆框架梁支护体系中框架梁和锚杆的受力特点,为地震引发滑坡灾害的防治提供依据.研究结果表明:框架梁的弯矩在锚头处取得最大值, 且随锚固预应力的增加而增大,但并不呈线性关系;即使在相同土质条件和同一锚固预应力作用下,坡脚处框架梁的弯矩要高于坡顶;此外,锚杆的预应力均存在一定的损失,施加的预应力值越高,预应力损失越大,且坡脚锚杆的预应力损失比坡顶小. 相似文献
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针对冲击地压造成大量锚杆支护结构破坏问题,采用动力数值计算方法,研究冲击载荷作用下锚杆-围岩的动力耦合作用与破坏机制。结果表明:(1)冲击载荷作用下锚杆与围岩振动存在明显的"时差效应",导致锚杆与围岩非同步振动,致使锚固剂承受动态剪切作用。随着锚固长度的增加锚杆与围岩的振动呈同步趋势,削弱了振动"时差效应"引起的锚固剂剪切作用,有效避免锚杆的脱粘滑移失效;(2)随着冲击速度的增大,"时差效应"导致锚杆锚固剂承受动态剪切作用被覆盖,锚杆的破坏失效模式由脱粘或杆体屈服断裂转变为锚杆与围岩统一破坏模式;(3)当冲击载荷频率接近锚固围岩体固有频率时,冲击载荷引起锚杆与围岩共振,锚杆与围岩同步振动速度幅值显著增大,可在相对较低的冲击速度下造成锚杆与围岩整体失效。远离锚固围岩体的固有频率对锚杆-围岩动力相互作用影响较小。 相似文献
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弹性反射波频谱分析对比法检测浆砌片石挡墙质量 总被引：2，自引：0，他引：2
钟世航 《CT理论与应用研究》2002,11(1):1-5
大量的浆砌片石挡墙需要作快速质量检测，作者比较了利用弹性波速、瑞利面波和弹性波频谱分析法后，认为后者分辨率高，方法简单，并作了几百个点的检测，得到了成功。 相似文献
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松散破碎岩体质量差、变形大、强度低,其加固技术难度大。合理有效的锚固技术是保证松散破碎岩体锚固效果的关键,采用压力分散型预应力锚索锚固因具有诸多优点而成为加固松散破碎岩体的有效技术。针对浙江金丽温（金华—丽水—温州）高速公路K81段边坡特点,综合考虑多种因素对支护设计方案进行优化,探索压力分散型锚索现场施工关键技术（如锚固力短期损失控制技术、补偿张拉控制技术和初始锁定值大小控制技术等）。现场监测数据表明,优化后方案可改善锚固效果,增强边坡稳定性。 相似文献
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地震激励作用下,柔性的锚杆支护体系与刚性的滑体合而为一,刚柔并济,协调系统位移与应力,主动抗震抗滑。基于以上优势,锚固边坡在高烈度地区广泛应用,其动力稳定性也成为近年来岩土工程领域研究的热点。通过分析锚固边坡的浅表动力效应、锚固体的动力响应、锚固体的破坏模式、锚固体的抗震机理及设计方法等4个方面发现,浅表动力效应研究和锚固体的动力响应分析研究成果相对较多、较成熟,但大都局限于位移、加速度、应力等单因素的分析,并没有具体到整个系统的动力响应过程;指出今后的研究方向更应趋向于整个锚固系统的动力响应过程、抗震机理及抗震设计理论,才能更好地为工程服务。 相似文献
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动荷载作用下边坡锚固系统合理设计探讨 总被引：1，自引：0，他引：1
爆破、地震或列车振动等动荷载作用下,边坡锚固系统易产生锚筋松弛、夹具损伤、注浆体拉裂及界面粘结失效等情况,影响其预应力赋存状态、加固效果和耐久性。基于动荷载作用类型和锚固系统动力响应特征分析,提出了动载下不同地层内的锚固段合理结构设计方案和锚筋抗拉安全系数及锁定荷栽的建议。动载下自由段（外锚固段）宜设计为全粘结型或增设多级反锚装置,形成岩土自锁锚固,以控制预应力损失和防止诸头或自由段破断造成突发性灾害;在水泥基灌浆体中掺入钢纤维或树脂纤维,可改善锚固体抗裂性能,提高其抗疲劳和抗冲击能力;建议优先采用防腐性能卓越的填充型环氧涂层钢绞线,以提高锚固体在动载破裂时的耐久性。 相似文献
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通过超声-时间动态测试方法系统地分析了煤系沉积岩石纵波和横波速度，计算了煤系岩石动弹性力学参数，同步测试了煤系岩石的静态力学参数，建立了煤系沉积岩石动弹性力学参数与静弹性力学参数之间和煤系岩石物理力学参数与其声波速度之间的定性定量关系.研究结果表明，煤系岩石的动弹性模量与岩石的纵波或横波速度具有很好的正相关关系，而与泊松比不具有这种正相关关系.煤系岩石的动弹性模量要大于其静弹性模量，而动泊松比要小于其静泊松比，它们之间呈线性相关关系.煤系岩石密度、单轴抗压和抗拉强度与其纵波或横波速度之间也呈正相关关系，它们分别服从二次函数、指数函数和线性函数分布. 相似文献
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本文采用基于FLAC^3D软件的数值模拟方法,对粤赣高速公路K3边坡工程锚杆的应力应变状态进行数值模拟,分析了全长粘结式锚杆的荷载传递机理;根据运用基于自发布里渊背向散射原理（BOTDR）的分布式光纤应变传感技术对锚杆的轴向应变进行的监测数据,分析了工程锚杆的变形特征。数值模拟与实测数据的对比分析表明,模拟曲线与监测曲线反映的工程锚杆的变形特征具有较高的一致性,验证了应用FLAC^3D有限差分软件模拟锚杆。框架体系应力应变特征的合理性,以及基于BOTDR的锚杆应变分布监测的可行性。 相似文献
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Summary In the present paper, the wave propagation from a cylindrical cavity in an infinite medium exhibiting couple-stress is considered. The variations of Hoop-stress on the cavity surface are investigated for different couple-stress material moduli and wave lengths. Significant differences are found when compared with those based on classical theory of elasticity. 相似文献
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The elasticity of minerals at high temperature and pressure(PT) is critical for constraining the composition and temperature of the Earth's interior and understand better the deep water cycle and the dynamic Earth. First-principles calculations without introducing any adjustable parameters, whose results can be comparable to experimental data, play a more and more important role in investigating the elasticity of minerals at high PT mainly because of(1) the quick increasing of computational powers and(2) advances in method. For example, the new method reduces the computation loads to one-tenth of the traditional method with the comparable precise as the traditional method. This is extraordinarily helpful because first-principles calculations of the elasticity of minerals at high PT are extremely time-consuming. So far the elasticity of most of lower mantle minerals has been investigated in detail. We have good idea on the effect of temperature, pressure, and iron concentration on elasticity of main minerals of the lower mantle and the unusual softening in bulk modulus by the spin crossover of iron in ferropericlase. With these elastic data the lower mantle has been constrained to have 10–15 wt% ferropericlase, which is sufficient to generate some visible effects of spin crossover in seismic tomography. For example, the spin crossover causes that the temperature sensitivity of P wave at the depth of ~1700 km is only a fraction of that at the depth of ~2300 km. The disruptions of global P wave structure and of P wave image below hotspots such as Hawaii and Iceland at similar depth are in consistence with the spin crossover effect of iron in ferropericlase. The spin crossover, which causes anomalous thermodynamic properties of ferropericlase, has also been found to play a control role for the two features of the large low shear velocity provinces(LLSVPs): the sharp edge and high elevation up to 1000 km above core-mantle boundary. All these results clearly suggest the spin crossover of iron in the lower mantle. The theoretical investigations for the elasticity of minerals at the upper mantle and water effect on elasticity of minerals at the mantle transition zone and subducting slab have also been conducted extensively. These researches are critical for understanding better the composition of the upper mantle and water distribution and transport in the Earth's mantle. Most of these were static calculations, which did not include the vibrational(temperature) effect on elasticity, although temperature effect on elasticity is basic because of high temperature at the Earth's interior and huge temperature difference between the ambient mantle and the subducting slab. Including temperature effect on elasticity of minerals should be important future work. New method developed is helpful for these directions. The elasticity of iron and iron-alloy with various light elements has also been calculated extensively. However, more work is necessary in order to meet the demand for constraining the types and amount of light elements at the Earth's core. 相似文献