Advanced mobility in difficult terrain

The development and success of the Swedish Combat Vehicle CV90 has demonstrated the abilities of the author in the field of terramechanics related to tracked military vehicles. The honour of the Bekker–Reece–Radforth Award 2002 has been granted in recognition of these achievements made during the author's employment at Hägglunds Vehicle AB since 1975. Hägglunds Vehicle AB has been a producer of military vehicles since the late 1950s, although the first years concentrated on production only. From the early 1960s, Hägglunds developed a number of its own tracked vehicles, all of which were influenced by the mobility demands dictated by their intended use in severe terrain conditions, such as those found in Northern Scandinavia. This paper presents a brief history of the advancement of tracked vehicle technology at Hägglunds Vehicle AB. The concepts discussed include: ground pressure, the number of road-wheels, articulated steering, track tension, track attack angle, sinkage, belly effects, and the use of terramechanic simulation. The success of the CV90 demonstrates that the combination of practical experience, terrain knowledge, and terramechanic simulations can effect substantial improvements in vehicle mobility. Evaluation of the CV90 versus other modern combat vehicles of the same class has shown that the CV90 possesses considerably higher mobility and speed under severe terrain conditions. These two attributes provide CV90 with the ability to access terrain that similar vehicles cannot, thus giving the military user greater mobility options.     

Ground state solitary waves for the planar Schrödinger-Poisson system

In this paper, we investigate the planar Schrödinger–Poisson System. Based on fixed point argument, Riesz’s rearrangement, Hardy–Littlewood–Sobolev inequality and critical point theory, we prove the existence and symmetry properties of ground state solitary waves. In addition to their existence, we also obtain the orbital stability of solitary waves.     

Using a Lumped Parameter Dynamic Model of a Rock Bolt to Produce Training Data for a Neural Network for Diagnosis of Real Data

Ground anchorage systems are used extensively throughout the world as supporting devices for civil engineering structures such as bridges and tunnels. The condition monitoring of ground anchorages is a new area of research, with the long term objective being a wholly automated or semi-automated condition monitoring system capable of repeatable and accurate diagnosis of faults and anchorage post-tension levels. The ground anchorage integrity testing (GRANIT) system operates by applying an impulse of known force by means of an impact device that is attached to the tendon of the anchorage. The vibration signals that arise from this impulse are complex in nature and require analysis to be undertaken in order to extract information from the vibrational response signatures that is relevant to the condition of the anchorage. Novel artificial intelligence techniques are used in order to learn the complicated relationship that exists between an anchorage and its response to an impulse. The system has a worldwide patent and is currently licensed commercially.A lumped parameter dynamic model has been developed which is capable of describing the general frequency relationship with increasing post-tension level as exhibited by the signals captured from real anchorages. The normal procedure with the system is to train a neural network on data that has been taken from an anchorage over a range of post-tension levels. Further data is needed in order to test the neural network. This process can be time consuming, and the lumped parameter dynamic model has the potential of producing data that could be used for training purposes, thereby reducing the amount of time needed on site, and reducing the overall cost of the system's operation.This paper presents data that has been produced by the lumped parameter dynamic model and compares it with data from a real anchorage. Noise is added to the results produced by the lumped parameter dynamic model in order to match more closely the experimental data. A neural network is trained on the data produced by the model, and the results of diagnosis of real data are presented. Problems are encountered with the diagnosis of the neural network with experimental data, and a new method for the training of the neural network is explored. The improved results of the neural network trained on data produced by the lumped parameter dynamic model to experimental data are shown. It is shown how the results from the lumped parameter dynamic model correspond well to the experimental results.     

大连开发区场地地震设计参数

根据工作区潜在震源区划分、潜在震源区地震活动性参数和地震动衰减关系, 进行场地地震危险性分析, 得到不同概率水平下场区相应地震烈度和基岩水平加速度峰值及其反应谱。根据场地工程地震条件划分不同地质单元及相应的场地类别, 进行不同概率水平的地震反应分析计算, 确定地震动设计参数。     

抽水引起的含水层水平应变──地裂缝活动新机理

基于Darcy -Gersevanov广义渗流关系式 ,本文首先导出了单井定流量抽水引起的泰斯承压含水层水平运动和应变解析表达式 ,并据此提出了抽水诱发地裂缝活动的含水层水平应变新机理 ,其主要观点为 :受井栅的约束阻挡作用 ,抽水活动将在含水层内部形成近井径向挤压区和远井径向拉张区两个应变区域 ,随着抽水时间的增长 ,近井径向挤压区将逐渐向外扩展 ;当地裂缝及其下伏断层或裂隙位于抽水活动引起的径向拉张应变区域时 ,地裂缝将出现加速活动 ;反之 ,当地裂缝处于抽水活动引起的径向挤压应变区域时 ,地裂缝活动反而受到抑制。上述地裂缝活动机理通过大同机车工厂现场抽水实验得到了初步证实。     

与地震相关的西安地裂事件的全过程研究

运用历史分析方法,通过物探、热释光测年、古建筑地震地裂反应分析等,探讨了新生代以来与地震相关的西安地裂事件全过程,初步建立了与地震相关的西安地裂事件历程,并按地质历史、地震记载历史、现代三个阶段讨论了地裂灾害特征。并结合地裂场地地震动力效应研究,对未来 5 0年内与地震相关的地裂危险进行了预测。本文成果不仅可指导西安城市建设规划,而且为地裂灾害工程抗防提供了依据。     

青藏铁路清水河地区路基下伏多年冻土地温变化特征研究

基于埋设在青藏铁路清水河地区路基中两个断面内的共8个地温测试孔3年来的地温观测资料,研究了该地区铁路路基下伏高原多年冻土融化特征,分析了多年冻土上限的变化规律以及填筑铁路路基施工对下伏多年冻土赋存条件的影响。研究表明,由于受到填筑路基时赋存在路基填料内的热量的影响,铁路路基下伏多年冻土近地表的地温变化特征与天然地面下的多年冻土的地温变化特征有明显的不同,且向阳面与被阴面差别较大。多年冻土的上限在施工初期会有一个明显的下移沉降,随着时间的推移,虽然残存在路基中的热量逐渐消散,多年冻土上限下降会逐渐稳定。由于受到太阳辐射和路基边坡形状及融化夹层的影响,多年冻土上限会逐渐稳定,但不会在短时期内上升到天然地面下多年冻土的上限水平。     

Effects of a roller and a tracked vehicle on the compaction of a high lifted decomposed granite sandy soil

The aim of this research was to innovate a new compaction machinery by comparing experimentally the effects of a two-axle, two wheel road roller and a tracked vehicle on the compaction of a decomposed granite sandy soil with a high spreading lift. By measuring the amount of sinkage of the terrain surface, the dry density distribution versus depth using a cone penetrometer, the normal earth pressure distribution versus depth using a stress state transducer (SST), the effects of the road roller and the tracked vehicle on the increment of the soil dry density were considered theoretically. It was observed that the tracked vehicle showed a larger amount of sinkage and a larger dry density distribution versus depth than the roller. The ratio of shear stress to normal stress was still large enough at the deep stratum, so that an optimal shear strain was developed on the whole range of the high lifted stratum and it increased the soil compaction density due to the dilatancy effect.