磁性材料专用磨床磨头体的有限元分析

文章在Hyperworks软件平台下对磨头体建立了有限元模型,并利用有限元分析得到了静力分析结果和模态分析结果。计算结果表明磨头体的强度和刚度可满足设计要求,机床工作时不会产生共振,确保了产品使用的安全性。     

软土地基换填施工模拟分析

文章针对软土地基换填施工的基本技术要求,运用数值方法模拟分析了软基换填施工过程中地基应力及位移的变化规律。经验证,其模拟分析结果能较好反映工程实际情况。     

Analysis of Responses of Pile Groups Due to Tunnelling during Excavation and Operation Periods Considering Rheological Behavior of Soft Soils北大核心CSCD

The additional pile responses due to the rheological behavior of the soil in the construction and operation periods of tunnelling are disadvantageous to the safety of the pile. However, among the current studies concerning with the rheological behavior of soft soil, the pile responses induced by the long-term settlement of 3D soil are seldom investigated. This paper mainly utilizes the finite difference software FLAC to discuss the pile response during excavation and operation periods considering rheological behavior of soft soil based on twostage analysis method. At the first stage, the displacement controlled method (DCM) is applied to simulate the short-time movement of soil during excavation period, the simulation results such as the shape of trough, pile responses such as pile deflection, settlement, axial force and bending moment are compared with the results of existing studies, and the numerical model is verified to be acceptable. At the second stage, the rheological behavior of soft soil is considered to estimate the long-term settlement of soil, the additional pile response is analyzed based on the CVISC model. Then, the influences of the four rheological mechanical parameters on the long-term soil settlement and pile responses are discussed and a fitting equation is proposed to estimate the long-term settlement of soil during the operation period. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Support Form and Construction Sequence for Soft Rock Tunnels with Small Spacing,High Stress and Deformation北大核心CSCD

Increasingly, stations are being extended to tunnels due to the effects of topography on mountain rail-ways and the requirements of the stations. A forked tail tunnel arrangement is the most popular one, but the concomi-tant effect of the following tunnel on the antecedent tunnel during construction of a tunnel with small spacing causes cracking of the primary support and secondary lining as well as heaving of the invert, which continues to trouble en-gineers. Different problems are encountered by different tunnels because of the complexities and variations of geo-logical environments. Using the construction of two single-line sections with small spacing for the Xinchengzi tunnel on the Lanzhou-Chongqing railway as an example, the support form for a soft rock tunnel with small spacing and high geostress and deformation, as well as the invert construction sequence of the left and right lines and secondary lining, are analyzed and discussed. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

新旧规程粗集料试验方法的对比

粗集料作为路面材料的重要组成部分,在整个路面工程中起关键作用。因此通过相关试验,检测粗集料质量的优劣就显得十分必要。     

沿海软土地区综合管廊运营初期结构病害调研及处理措施——以徐圩新区综合管廊为例

目前我国综合管廊建设规模较大,且多数分布在沿海软土地区,在运营初期廊内普遍存在病害发展较快且较隐蔽等问题。基于处于运营初期的连云港市徐圩新区城市地下综合管廊实际工程案例,针对管廊内存在的裂缝、渗漏、积水、错台等病害进行调研与分析。根据检查结果分析管廊病害发生原因并提出相应解决措施,为类似地质条件下的综合管廊建设和维养提供了参考和借鉴。     

水泥加固软土路基的强度特征及微观结构分析

利用化学分析、电镜扫描分析、无侧限抗压强度等实验,分析天然软土、水泥土样品宏观及微观特征,找出宏观力学性质和微观变化之间的关系。由于水泥的掺入,使土体易于压实,孔隙体积减小,且能生长出纤维状矿物使密实度提高,从而提高土的强度。并且从微观分析研究了水泥土加固软土的作用机理。     

深厚层软土地基袋装砂井处治的数值模拟

基于平面变形、空间渗流(PDSS)理论,从路基工后沉降角度出发,用岩土工程静力分析有限元程序PDSS2000,进行袋装砂井处治深厚层软基的数值模拟分析,研究全过程的软基沉降、侧移、孔压分布规律。结果表明,袋装砂井能有效加速软基的排水固结。对于福厦线一般地段,当路基高度为6m时,采用间距为1 0m的袋装砂井处治软基能满足路基工后沉降要求。     

地下水对董志塬黄土隧道工程性质的影响分析

地下水对新建隧道工程具有诸多不良影响,通过现场调研和资料整理,对董志塬区黄土地层性质和地下水分布特征进行系统总结,分析董志塬地下水对银西高铁隧道工程的影响。结果表明:(1)董志塬区黄土物理力学性质随地层岩性、位置和地下水位变化存在一定的差异性,含水率和液性指数从塬边南部向塬边北部依次减小,孔隙比和压缩模量从塬边南部向塬边北部依次增大;(2)董志塬区地下水位埋深在塬心浅而塬边深,北塬地下水位埋深略比南塬深;含水层厚度则在塬心比较厚,而向塬边逐渐减小;(3)董志塬区地下水对银西高铁黄土隧道工程的主要不良影响有:引发黄土湿陷性;形成软塑状黄土;导致隧道管涌、涌水、塌方、冒顶事故等。     

旋喷桩联合花管注浆加固既有普速铁路软基施工应用技术研究

通过对旋喷桩、花管注浆的设备选型、材料制备、施工顺序、成桩(孔)控制、变形监测及质量检测等施工技术方面进行研究,提出旋喷桩联合花管注浆施工的相关技术及施工参数,解决在不影响既有线运营的情况下,用于普速铁路既有线软土地基处理并达到了理想的加固效果的难题。建议在具体应用中结合土性、施工条件、设备类型等因素确定适宜的参数。