吹填砂场地强夯振动特性研究及安全评估

针对曹妃甸工业园区液化天然气储罐地基加固过程中所引起的地面振动进行了深入研究,通过对现场强夯振动观测记录进行统计分析、频域分析以及规律拟合,给出了吹填砂场地上强夯所引起的地面振动衰减规律、振幅（振速）随夯击次数的变化规律以及强夯振动的主频变化规律,并就场地周围已存的海堤工程和天然气储罐工程进行了振动安全评估,为现场强夯施工参数的选取提供了理论支撑,同时也弥补了国内对于类似场地振动特性研究不足的局面。     

庐江-枞阳火山岩矿集区南部城山地区地质条件和成矿规律研究

庐江-枞阳(庐枞)火山岩矿集区南部作为寻找沉积-叠加改造型铁铜矿的有利地区一直没有较大找矿突破,该区近几年勘查取得了一定地质找矿进展。本文主要在野外地质调查的基础上,对庐江-枞阳火山岩矿集区南部城山地区地质条件进行总结分析,重新认识了区内地层的含矿性以及构造特征,发现了大量矿化线索。在研究区内发现了4条与岩浆热液有关的铜铁铅锌矿化带,而且具有一定规律,空间上平面均为北东东、东西向,垂向上从深到浅具有从钼到铜铅锌矿化分带。成矿时间从126.5Ma开始。研究区内大规模磁铁矿化以及铜铅锌矿化的存在,表明深部具有较好找矿潜力。     

离心实验在污染物迁移研究中的应用

离心实验模拟以其可以获得与原型一致的应力水平并且能够大大缩短原型历时而被应用于污染物迁移实验研究。在离心相似理论及离心实验模拟的相似基础上,重点回顾了离心机在饱和带水分、非饱和带水分、保守性溶质、NAPLs、重金属、核素迁移以及污染场地修复方面的实验应用。最后讨论了离心模拟中土壤预制和加速度选择的问题,并简单介绍了离心监测方法。可以得出结论:离心机能够成功用于各类物质迁移的实验研究中,离心实验模拟能够为理论和数值等分析方法快速提供真实可靠的参数依据,但离心实验的理论基础和监测方法需要进一步完善,此外也应积极开展更接近实际情况下的离心实验模拟研究。     

花都地区岩溶发育规律及影响和控制因素调查研究

本文介绍了区内主要岩溶含水层分布规律、富水性等情况,并分别从岩性、地貌、构造、埋深、地下水活动及古水文网发育状况等方面,分析了其对岩溶发育的影响。     

三轴冲击荷载作用下淤泥力学响应研究

利用SPAX-2000（改进型）静动真三轴系统,针对淤泥类超软土进行静动力排水固结试验,研究包括较高频率在内的各冲击荷载频率（1、8、16 Hz）与不同围压（200、250、300 kPa）作用下淤泥的力学响应;此外,结合三轴剪切试验研究不同固结条件对淤泥不排水强度的影响。试验结果表明：（1）在相同冲击频率作用下,试样抗剪强度随着围压增大而提高;围压增大,使得球应力增大,体应变随着增大,有效地促进试样排水固结。（2）相同围压作用下,存在着一个冲击荷载频率阈值,当冲击频率低于这一阈值时,随着冲击荷载频率的提高,轴向应变量逐渐变小,反之逐渐变大。（3）冲击瞬间,体应变为负值,表现为体胀,这与原位试验夯击瞬间的孔隙水压力变化曲线一致,从而验证了高含水率淤泥在冲击作用下的孔压负增长现象。     

潞安矿区井下地应力测量及分布规律研究

在山西潞安矿区的13个煤矿采用小孔径水压致裂地应力测量装置,完成了60个测点的原岩应力测量工作。实测数据表明：潞安矿区55%的测点最大水平主应力大于垂直主应力,由于受埋藏深度与地质构造影响,矿区内各矿地应力值差别较大,但地应力大小总体上属于中等地应力值;潞安矿区最大水平主应力方向从南到北变化较大,构造应力场呈现出多变的形态。在实测数据的基础上,绘制了潞安矿区地应力分布图;分析了地应力随埋藏深度的变化规律、平均水平主应力与垂直主应力的比值与埋藏深度的关系。煤矿井下地应力测量为井田开拓、巷道布置与支护设计等工程实践提供了可靠的基础参数,提高了工程设计的科学性、合理性与可靠性。     

The coalescence of water drops II. The coalescence problem and coalescence efficiency

By the use of the model of approaching drops (Arbel and Levin, 1977) the coalescence efficiencies of drops are computed. It is found that for interactions of drops at their terminal velocities the coalescence depends both on the size of the large drop and on the size ratio of the interacting drops in agreement with the experimental results of Whelpdale and List (1971) and Levin and Machnes (1977).The results were found to be sensitive to the assumption of the drops deformation and to the critical separation distance. This distance is defined as the distance at which the drops begin to merge. The variations of the coalescence efficiency with these parameters is discussed.Appendix: List of symbols D distance between the deformed surfaces of the drops - D _o initial value ofD - D _s stop distance, the distance at which the impact velocity vanishes - D _c critical coalescence distance - E collection efficiency - E ₁ collision efficiency - E ₂ coalescence efficiency - E _2R coalescence efficiency for collisions with stationary targets - F _c centrifugal force - p ratio of the radii of the interacting drops - r _o initial distance between drops' centers - R _L radius of larger drop - R _s radius of smaller drop - R _D radius of deformation - v approach velocity of two deformed surfaces - v _o initial value ofv - V _i impact velocity (given negative sign when drops approach each other) - V _c critical impact velocity - W _i velocity of the smaller drop at infinity for it to reachD _o with velocityv _o - x _i impact distance, the distance between the trajectories of the two drops - x _c critical impact distance for coalescence -  average critical impact distance for coalescence - X _c critical impact distance for collisions - coefficient of deformation given in equation 1 - _i impact angle defined byWhelpdale andList (1971) given also inArbel andLevin (1977) - coefficient of deformation given in equation 2 - viscosity of air - _i impact angle used inArbel andLevin (1977) and here - _c critical angle for coalescence - average critical angle for coalescence On sabbatical leave (1976–77) from the Department of Geophysics and Planetary Sciences, Tel Aviv University, Ramat Aviv, Israel.The National Center for Atmospheric Research is sponsored by the National Science Foundation.     

Multi-directional modeling for prediction of fabric anisotropy in sand liquefaction

Anisotropy in the onset of liquefaction and post liquefaction under cyclic loading condition causes the change in response behavior of the soil. The proposed model operates within the integration of sliding/opening/closing framework of 17 predefined planes as local deformation. This leads to the use of better stress/strain multilaminate histories with many directional effects on soil behavior specifically internal mechanism during pre and post-liquefaction. The ability of multilaminate model for fabric anisotropy has been proven by comparison with the experimental results under drain and undrained conditions and monotonic and cyclic loading. The effects of induced anisotropy was also investigated.     

Centrifuge modelling of landslides and landslide hazard mitigation: A review

Landslides are serious geohazards that occur under a variety of climatic conditions and can cause many casualties and significant economic losses. Centrifuge modelling, as a representative type of physical modelling, provides a realistic simulation of the stress level in a small-scale model and has been applied over the last 50 years to develop a better understanding of landslides. With recent developments in this technology, the application of centrifuge modelling in landslide science has significantly increased. Here, we present an overview of physical models that can capture landslide processes during centrifuge modelling. This review focuses on (i) the experimental principles and considerations, (ii) landslide models subjected to various triggering factors, including centrifugal acceleration, rainfall, earthquakes, water level changes, thawing permafrost, excavation, external loading and miscellaneous conditions, and (iii) different methods for mitigating landslides modelled in centrifuge, such as the application of nails, piles, geotextiles, vegetation, etc. The behaviors of all the centrifuge models are discussed, with emphasis on the deformation and failure mechanisms and experimental techniques. Based on this review, we provide a best-practice methodology for preparing a centrifuge landslide test and propose further efforts in terms of the seven aspects of model materials, testing design and equipment, measurement methods, scaling laws, full-scale test applications, landslide early warning, and 3D modelling to better understand the complex behaviour of landslides.     

热模拟实验中低变质煤的突出参数变化特征

为了研究瓦斯突出煤体的演化过程,采用煤化变质热模拟实验装置对煤样进行热模拟实验,分析不同实验温度条件下煤样的产气量、气体组分及加热前后煤体结构性能参数的变化规律。结果显示：在较高的实验温度下（450℃）产生的气体总量比较低温度（200℃）下大得多,前者的产气量几乎是后者的10倍,且相应的煤挥发分、坚固性系数和瓦斯放散初速度变化了5~7倍;350℃左右是低变质煤热解大量产生CH₄和焦油的临界温度,且在此温度时,低变质煤的坚固性系数和瓦斯放散初速度值已经超过突出煤层鉴定指标。由此认为,温度能改变煤体化学结构并产生瓦斯气体,且大量瓦斯气体的生成改变了煤的物理结构,其综合作用表现为煤体更易破碎,其突出危险性增加。