利用声波测井计算岩石的力学参数

介绍了岩石力学参数的测量方法及岩石动、静弹性参数相关关系,最后用实际声波测井资料来分析计划岩石的力学参数。     

On Tension Failure of 2-D Rock Specimens and Associated Acoustic Emission

Summary To understand the failure mechanism of quasi-brittle materials like rock under tensile stress, observations on the failure process of granite and marble plate specimens under tension are summarized and presented. Micro- and macro-failure properties of rock plates under uniaxial tension have been characterized by using an acoustic emission technique. Acoustic emission signals associated with micro-fractures are captured to locate the sources. An algorithm based on arrival time difference is developed for this purpose. The results reveal clearly the failure processes of rock which include initiation, nucleation and propagation of micro-fractures when the axial stress is close to the peak strength of rock. It is believed that the difference in heterogeneity between granite and marble specimens leads to different fracture shapes and different behaviors of associated acoustic emissions. Numerical simulation of acoustic emissions for two-dimensional tensile test is also carried out. The simulated characteristics are in good agreement with the experimental results.     

滚石在平台上的运动特征分析

危岩体;滚石;平台;运动距离;现场试验;滚动摩擦系数     

复杂构造条件下大型地下工程开挖局部不稳定块体分析与预测

锦屏一级水电站泄洪洞位于雅砻江右岸埋深大于100m的大理岩中,构造条件复杂,在施工开挖过程中产生大量不稳定块体,严重影响工程安全。本文以泄洪洞0＋210～0＋230m段中导洞现场工程为依托,根据所揭露出的工程地质条件,采用赤平投影、统计分析和块体理论等手段,对该工程段可能存在的不稳定块体进行了分析和预测。分析得到如下结论：（1）未开挖段不稳定块体由fxh-14、fxh-16断层与②、④组节理和开挖临空面切割产生,主要分布在右侧拱脚部位;（2）可能的大小主要取决于②、④组结构面的延伸长度;（3）搜索结果表明：未开挖段右侧拱脚处存在两处大型块体。经块体理论计算,其中由L一。。与②、④组节理和临空面组合而成的不稳定块体体积26．8m3,稳定性系数2．89。而fxh-14、fxh-16断层、②组节理与临空面切割而成的不稳定块体体积25．40,破坏模式为直接掉落,应施以相应的工程支护补强措施。     

用声波参数确定岩石加载破坏过程的不同阶段

本文研究了岩石在单轴和真三轴加载的破坏过程与声波参数及动力学参数之间的关系。在单轴和三轴压缩实验中,通过测量纵横波速度和振幅的变化,有效地判断岩石加载和结构的变化情况,确定岩石加载破坏过程中的几个阶段,实现对岩石破裂前兆的预测。本文还研究了三轴压缩实验中中间主应力σ_2的改变对声波速度和振幅变化曲线的影响。     

Assessment of the Excavation-Damaged Zone in a Tall Rock Slope Using Acoustic Testing Method

During slope excavation, high stresses can become concentrated in the rock mass because of stress redistribution. Failure of the rock mass creates an excavation-damaged zone (EDZ) in the slope. The damage reduces the acoustic wave velocity in the rock mass. Results of field tests measuring acoustic wave velocity at the Jinping I Hydropower Station are used here to study the EDZ in a tall rock slope. Two acoustic testing methods were adopted in the field tests: single-hole acoustic testing (SAT) and cross-hole acoustic testing (CAT). The acoustic wave velocity was lower in the EDZ, and the depth of the EDZ increased with decreasing slope elevation. Statistical analysis shows that the acoustic wave velocity obtained by the SAT method is larger than that obtained by the CAT method, and the relative difference between the SAT- and CAT-derived velocities is lower for a high quality rock mass than for a low quality rock mass. The integrity ratio and severity of damage can also be determined by acoustic wave velocity test results, revealing that the integrity ratio and elastic modulus of a rock mass are reduced in the EDZ.     

Failure and Acoustic Emission Characteristics of Jointed Rock Masses with Different Joint Inclination Angles and Combination Mode

Geotechnical and Geological Engineering - In order to analyze the characteristics of the mechanical property, failure mode and acoustic emission of the columnar jointed rock masses,...     

水对不同岩石声波速度影响的研究

通过分析不同成因类型岩石的声波速度,提出了水对不同岩石声波速度的影响,从岩石孔隙及隐微裂隙的发育程度及岩石的水理性质解释了在水的作用下岩石声波变化规律,利用这些规律可以初步判断岩石的隐微裂隙发育程度及水理性质。     

Experimental Study of Failure Zone in Soil and Rock Blast

In this paper, according to in situ experimental data of sonic, seismic, hole television, acceleration, velocity and visual investigaton after explosion, we consulted laboratory experimental results. Study in soil and rock blasr destroy effect and zone. By comparing with blast destroy zone of rock mass, vartical tunnel, parallal tunnel.     

土岩爆破中岩体和坑道爆破破坏分区的试验研究

本文根据声波法、地震法、钻孔电视、质点振动加速度、速度和爆后破坏现象宏观调查等现场实验数据和资料,并参照室内试验结果,研究了土岩爆破中岩体和坑道的爆破破坏效应及其分区、并将岩体、垂直坑道与平行坑道的爆破破坏分区作了对比。     

Study on Deformation Failure Mechanism and Control Technology of Surrounding Rock in Soft Rock Roadway

Geotechnical and Geological Engineering - In order to reveal the mechanism of surrounding rock deformation and instability of soft rock roadway in 12# working face of Puhe coal mine, and...     

金川软岩蠕变破坏机理电镜实验研究

为探讨金川矿岩石蠕变破坏机理,应用微观扫描电镜(SEM)对蠕变受力情况下岩石破坏断口微观形态进行了观察研究,并分析了其产生的微观破坏机制。结果表明:岩石蠕变断裂的微观机制主要是拉伸、剪切作用下岩石发生脆性断裂,从岩石断裂微观形态研究岩石蠕变断裂,可以更好的揭示岩石断口微观形貌特征、裂纹生核、扩展、及断裂方式与岩石蠕变演进过程的联系。     

Rock Type Identification Using Analysis of the Acoustic Signal Frequency Contents Propagated While Drilling Operation

Geotechnical and Geological Engineering - One of the most important parameters specially in mining and oil drilling fields is the type of rocks. It is important to determine that rock structure is...     

Numerical Study of Failure Mechanism of Serial and Parallel Rock Pillars

Using a numerical modelling code, rock failure process analysis, 2D, the progressive failure process and associated acoustic emission behaviour of serial and parallel rock samples were simulated. Both serial- and parallel sample models are presented for investigating the mechanism of rock pillar failure. As expected, the numerical results show that not only the stiffness, but also the uniaxial compressive strength of the rock plays an important role in pillar instability. For serial pillars, the elastic rebound of a rock pillar with higher uniaxial compressive strength can lead to the sudden failure of an adjacent rock pillar with lower uniaxial compressive strength. The failure zone forms and develops in the pillar with lower uniaxial compressive strength; however, the failure zone does not pass across the interface of the two pillars. In comparison, when two pillars have the same uniaxial compressive strengths but different elastic moduli, both serial pillars fail, and the failure zone in the two pillars can interact, passing across the interface and entering the other pillar. For parallel pillars, damage always develops in the pillar having the lower uniaxial compressive strength or lower elastic modulus. Furthermore, in accordance with the Kaiser effect, the stress-induced damage in a rock pillar is irreversible, and only when the previous stress state in the failed rock pillar is exceeded or the subsequent applied energy is larger than the energy released by the external loading will further damage continue to occur. In addition, the homogeneity index of rock also can affect the failure modes of parallel pillars, even though the uniaxial compressive strength and stiffness of each pillar are the same.     

施工期岩锚梁岩台破坏模式及稳定性分析

针对西南某大型水电站地下厂房岩锚梁岩台区节理发育的特点,并考虑辉绿岩脉等软弱带的影响因素,结合现场调查,利用关键块体理论方法分析得出开挖过程中岩台主要破坏模式为滑动、滑移—拉裂、弯曲—拉裂以及辉绿岩脉松动溃散4种,其中,上、下直墙的陡倾角结构面组合特征及辉绿岩脉的发育直接影响岩台的成型与稳定,开挖过程中针对各发育特征采...