Estimating Abrasivity of Rock by Laboratory and In Situ Tests

The degree to which a rock abrades another rock is called its “abrasivity”. Laboratory tests of abrasivity can be broadly divided into four kinds: drilling, rubbing, turning-operation and tumbling tests. The present study was initiated 30 years ago with the objective of investigating and developing methods for measuring rock abrasivity, and making some contribution towards understanding the relationships between the above test methods. Within the range of tests conducted, the turning-operation test turned out to be superior to the drilling test, albeit slightly, in terms of practicality. We have also conducted in situ tests using rock drills for the last 20 years. The results of those tests have been investigated and compared with the results of laboratory tests. There is a large degree of scatter in the data on gauge loss in button bits, which has obscured any correlations with laboratory data. Some correlations were found between height loss in button bits and laboratory findings.     

Experimental Analysis and Micromechanical Modelling of Dry Granular Flow and Impacts in Laboratory Flume Tests

Summary. The paper presents the results of a numerical analysis, carried out by using the Discrete Element Method (DEM) and aimed at reproducing a series of tests on a small-scale laboratory model of a slope. Particular attention is devoted to the validation of DEM when used for the prediction of the run-out distance and of the impact force on obstacles. The soil used for the small-scale model is a mono-granular medium sand, which revealed to be particularly suitable to simulate flows like debris or rock avalanches. The experimental set-up comprises a flume equipped with a system of differently sized instrumented obstacles. The numerical model of the granular flow has been calibrated on the basis of the displacement measurements, obtained through a photogrammetric technique. Author’s address: Roberto Valentino, Department of Civil, Environmental, Territorial Engineering and Architecture, Università degli Studi di Parma, Parma, Italy     

桩土相互作用模型及模型实验

本文介绍了目前在桩基测量及计算中使用的一些桩土相互作用摸型,同时也介绍了在动载情况下研究桩土相互作用的模型实验,并将桩土模型的计算与实验结果进行了比较和分析。     

地质钻探铝合金钻杆材料研制及室内试验研究

与钢钻杆相比,铝合金钻杆具有比强度高、刚度低、耐腐蚀性好等优点,在实施钻探工程作业时,可增加现有钻探设备钻进能力,减少钻机动力消耗,降低钻探施工难度,减轻工人劳动强度.开展地质钻探铝合金钻杆研究,对提高我国难进入地区地质调查钻探工程效率、推动地质钻探科学技术进步以及节能降耗工作具有重大现实意义.本文介绍了7E04铝合金...     

Field and Laboratory Tests Investigating Settlements of Foundations on Weathered Keuper Marl

Measured settlements of buildings on the weathered Keuper Marl appeared to be much smaller than calculated settlements, which were based on stiffness modulus from standard oedometer tests. Therefore, both special triaxial K ₀-tests and oedometer tests were carried out for an accurate determination of stiffness moduli. Modulus obtained in the triaxial K ₀-tests were at least two to three times the values obtained in the oedometer tests. To verify observations from the laboratory tests, the loads and the settlements of two single footings on weathered Keuper mudstone have been measured during construction of a building over 1 year. Also, a large scale footing load test with measurements of deformations were conducted on the weathered Keuper mudstone. The measured settlements of the two single footings and the tested foundation were compared with the settlements based on conventional calculations with moduli from oedometer tests and triaxial K ₀-tests. Up to a foundation pressure of σ_v = 500 kN/m2 the calculated settlement based on E _S-modulus obtained from triaxial K ₀-tests was found to correspond well to the measured deformation. For foundation pressure beyond 500 kN/m2, the foundation response was highly non-linear and it could not be described any more with the linear-elastic model. Therefore the footing load test was also simulated by FEM analyses.     

Laboratory Tests on Shotcrete-Rock Joints in Direct Shear, Tension and Compression

Summary. A series of laboratory tests was performed on cemented shotcrete-rock joints to investigate the strength and stiffness of the interfaces, while simulating field conditions as close as possible. The direct shear test formed the core of the experimental work, while the tension and compression tests were complementary. To simulate loading conditions experienced in practical cases the direct shear tests were performed under fairly low normal stresses. In most practical cases when shotcrete is used with rock bolts, the normal load on shotcrete lining seldom exceeds 0.2 to 0.5 MPa. The direct shear test results show that, for such normal load range the shear strength is determined by the bond strength for genuinely bonded shotcrete-rock interfaces. For higher normal stresses (σ_n > 1.0 MPa), which rarely exist at the shotcrete-rock interface, the shear strength is largely influenced by friction resulting in the cohesive strength being less significant. Assessment of the shear surface revealed that the steel fibres in the shotcrete appeared to contribute significantly to the frictional component. The shear and normal stiffnesses of the interface were also determined, which were in principal the stiffnesses of the bond. An interesting observation was the complex interaction at the interface and the mechanisms that controlled the peak shear strength which depended on the surface roughness, the existence of natural flaws and the normal load.     

定向裂缝对地震波速度和振幅影响的比较—实验结果分析

利用垂直定向裂缝模型和MTS岩石物性测试系统，测试了不同材料和不同状态裂缝模型的地震特征响应。对特征响应进行分析和比较后发现，虽然波的传播速度，振幅，吸收衰减，主频均可用来检测裂缝的特征参数，但是裂缝变化对振幅的影响大于对速度的影响。因此，利用地震波的振幅、衰减等属性参数检测裂缝特征比利用速度参数更有效。     

Validation of Hyperbolic Model by the Results of Triaxial and Direct Shear Tests of Municipal Solid Waste

The increasing demand of engineering landfills requires that designers propose a framework for landfill design, construction, repair and maintenance. As municipal solid waste (MSW) is a major part of a landfill, the analysis should consider MSW mechanical behavior using a constitutive model. To investigate this, 18 direct shear (DS) and triaxial (TX) tests were conducted on MSW samples with different fiber contents. Different shearing mechanisms lead to understand effects of fibers on stress–strain response. Based on obtained results the hyperbolic model Duncan and Chang (J Soil Mech Found Div 96(5):1629–1653, 1970) has been employed to simulate the TX results indicating the ability of the model to predict stress–strain behavior of MSW. This model could also be employed to the DS test results with some assumptions. The model can capture DS stress–strain response well whereas for TX tests the predictions were just enough. The experimental results and two sets of proposed MSW parameters of hyperbolic model have been compared and discussed.     

Numerical and Laboratory Analysis of Relaxation Tests for Determining Time-Dependent Properties of Rock

Roof falls in coal mines may occur within a few months to a few years after excavation. In this paper, we proposed the use of relaxation tests as a substitute for time-dependent tests. The relation between creep behavior and relaxation behavior was numerically investigated and demonstrates that the material assigned with creep model can show relaxation behavior. Then the relaxation model was developed by modifying the Burgers creep model. Numerical simulation of a relaxation test on a simulated rock model in 3DEC yielded results that were similar to theoretical prediction. A relaxation test was performed on two groups of specimens under varying load conditions. Results from the laboratory tests validated the approach of using relaxation test to determine time-dependent properties. Finally, time-dependent properties were investigated by performing relaxation tests at different stages of a complete stress–strain curve. The relaxation test during strain-softening was unsuccessful; however, the relaxation behavior at residual stage in post-failure region was more significant than that in pre-failure region and the sudden drop in stress indicated there was strength deterioration due to the accumulation of viscous strain.     

密闭体系与开放体系模拟实验结果的比较研究及其意义

利用广泛应用的高压釜和Rock Eval热解实验技术，对松辽盆地3个有机质样品同时进行了密闭条件下的加水恒温热解实验和开放条件下的恒速升温热解实验。利用后一实验数据所标定得到的化学动力学模型计算了与高压釜相同实验条件下的有机质产油、产气率。结果表明，在线计量的恒速升温Rock Eval实验方法由于不损失C6—C13的轻质烃组分，在计量液态油的产量方面较需要抽提、恒重的高压釜实验方法更为准确。因此为解决热模拟实验中难以计量、但对成烃评价有重要意义的C6—C13组分的计量问题提供了一条有效的途经。这可能也表明，先由实验数据建立有关的化学动力学模型，之后由它来进一步计算有机质的成烃率，不仅是可行的，而且应该更为准确。     

浅层岩土室内、外热物性测试的相关性

对于浅层岩土热物性参数测试中常用的实验室和现场热响应试验方法,结合上海某工程的实际情况,提出一种基于室内试验的岩土综合热物性参数确定方法。首先,根据室内、外试验测试结果的差异,选取地层厚度、含水率、密度及渗透系数作为影响二者热物性参数测试差异的主要因素,使用层次分析法确定各影响因素的权值,并按权值大小修正室内热物性参数测试结果。然后,分别模拟室外现场热响应试验和修正后的室内热物性参数以及实际地层的传热过程,得出三者在热量传导能力之间的差距分别为1.2%、1.1%及2.3%。最后,提出埋管深度和导热系数的乘积可代表岩土层的换热能力,且计算出修正后的室内热物性参数对应的均一导热系数与现场热响应试验测出的综合导热系数分别为1.832 W/(m·℃)和1.778 W/(m·℃)。     

影响气泡轻质土工材料施工稳定性的因素及其试验研究

气泡轻质土工材料在软基加固、减小土压力等方面有着广泛的应用。通过试验分析的方法 ,主要探讨了影响气泡轻质土工材料施工稳定性的因素及相应的提高和改善施工稳定性的方式 ,为工程应用提供了必要的依据。     

羽纹构造和蚌纹构造的理论及实验研究

将节理面上的羽纹构造和蚌纹构造划分为８种类型，单羽构造，双羽构造，叉羽构造，弯羽构造，半羽构造、反羽构造，蚌纹构造和羽蚌复合构造，应用数学分析和物理实验对羽纹和蚌纹进行了定量模拟。数学模拟表明，单羽构造和半羽构造的羽缘角理论值７２°和８３°，天然岩石中的单羽构造和半羽构造羽缘角的统计平均值分别为７５°和８０°。     

Geothermobarometry in Four-phase Lherzolites I. Experimental Results from 10 to 60 kb

Experiments were carried out on primitive natural lherzoliticcompositions from 10 to 60 kb and to 1400?C. Mineral compositionswere reversed by using mixes of finely ground (<20µm)minerals from natural rock samples with different initial compositions.The minerals were mixed in proportions to give a primitive uppermantle composition. Further starting materials were a syntheticmineral mix and a sintered oxide mix. Equilibrium was thus approachedfrom different chemical directions, and equilibrium mineralcompositions were inferred from the overlap of microprobe analyses.Fe-loss problems were avoided by using single-crystal olivinesas sample containers. Samples were placed into holes drilledinto cylindrically shaped olivine crystals, which in turn werewelded into Pt capsules. A further advantage of this methodis that oxygen fugacities seem to be buffered by the Ni precipitationcurve. This curve lies very close to the iron-w?stite (IW) buffercurve for mantle olivines. Oxygen fugacities calculated fromcompositions of experimentally produced spinels give valuesslightly above the IW buffer curve. Therefore, practically noFe³⁺ should be present in our experimental charges. Ortho- and clinopyroxene compositions were strictly reversedwith respect to Al Cr, and Na (only cpx) contents and theirmutual amounts of enstatite and diopside components. The datashow the fundamental influence of Na in cpx on two-pyroxenethermometry. Garnet compositions were reversed with respectto Ca, Al, Cr, Ti, and Mn. Other than in CMAS, Ca in garnetis mostly dependent on temperature in the natural system andnot so much on pressure. This behaviour of Ca will most stronglyinfluence barometers based on the Al content of orthopyroxenecoexisting with garnet. The mg-numbers of coexisting phaseswere not strictly reversed. The homogeneity of olivine compositionsand internal consistency of the data set give us confidencethat equilibrium values of mg-number have been reached in almostall cases. The experimental results presented in this paperoffer the unique possibility of simultaneously testing manydifferent thermobarometers which are based on dfferent exchangereactions and which were calibrated in different laboratories.     

冻结管受力分析与试验研究

对冻结管受力的理论分析和模拟试验研究表明,在安装阶段,冻结管的应力很小,可略去不计,在积极冻吉阶段,受管材冷缩。冻土冷缩和冻土冻胀的作用,冻结管轴向受拉（压）并向井外弯曲,在该阶段后期,纯拉（压）应力σ１由正最大值和负值转变,且数值变小,而纯弯曲应力σｗ则趋于稳定,其值虽较大但对后期冻结管的安全无害,在掘砌施工阶段,冻管的受力大小决定冻结壁的变化形,σ１和σｗ随时间的变化规律与冻结壁的蠕变规律相似