对水工建筑物地基加固防渗措施的探讨

由于地基原因引起水工建筑物失事的例子很多,因此,我们必须重视水工建筑物的地基处理。本文介绍了水工建筑物地基加固防渗方法,对一般水工建筑物工程,提供价值性的参考。     

地基沉陷建筑物承受附加作用力的计算方法

针对地基沉陷对建筑物的作用,研究受地基沉陷影响建筑物产生的附加作用力.分析了地表水平变形、地表曲率变形引起建筑物的附加作用力和层间水平砌体带所受附加剪力及其产生的附加弯矩,给出了其计算公式.对分析建筑物受地基沉陷影响的程度和使用的安全性,研究地基沉陷区已有建筑物的保护,以及进行地基沉陷区新建建筑物的设计具有指导意义.     

从建筑物墙体裂缝谈地基处理问题

通过对既有建筑物地基变形、墙体裂缝的实际调查,分析了地基处理的重要性,进而对建筑物地基处理提出了意见.     

建筑物的复合地基分类和特性探讨

众所周知．地基作为建筑物上部结构的基础部分处在地表下部．这就给建筑物地基提出了严格的要求。当天然地基不能满足建筑物对地基的要求时．需要进行地基处理,形成人工地基,以保证建筑物的安全与正常使用。地基处理方法很多,总体讲,常用基础形式可归类为复合地基、浅基础、桩基础三种。浅基础和桩基础两种我们经常接触,对于复合地基较为陌生．但近些年来复合地基在建筑工程、     

利用灌注桩进行地基加固纠偏的工程实例

利用灌注桩进行地基加固的同时对倾斜建筑物进行纠偏处理是一种全新的建筑物基础托换与地基加固方法。通过对某危房进行纠偏和地基加固的工程实例,阐述了利用灌注桩进行建筑物纠偏和地基加固的设计思想和施工要点。     

从砖混结构墙体沉降裂缝谈其地基处理的质量监控

通过对建筑物承重墙体裂缝、地基沉降、变形的调查,分析了地基处理对防止、控制承重墙体裂缝的作用。进而提出了对建筑物地基处理及过程的质量监控。     

素混凝土桩复合地基在西安地基处理工程中的应用

针对建筑物对地基承载力和变形的要求和地层性状,结合素混凝土桩复合地基的特点,采用素混凝土桩复合地基进行地基处理,并对复合地基参数进行了设计。通过试桩试验和工程桩的检测,表明素混凝土桩复合地基对地基承载力提高幅度大,减少地基变形明显,很好地满足了建筑物对地基承载力和变形的要求。     

浅谈结构设计中地基处理的意义

在现代建筑工程设计中,建筑物高度和结构复杂程度在不断提高,相应地建筑物对地基的承载能力要求越来越高,原位地基特别是软土地基大多满足不了建筑物对它的要求,而地基处理对确保地基的稳固性具有非常重要的作用。本文就地基处理进行介绍,对建筑结构设计者地基处理的意义进行阐述。     

预防相邻建筑物地基沉降的处理方法

从外因和内因两方面分析了相邻建筑物地基产生沉降的原因,对相邻建筑物地基产生沉降的变形特征进行了探讨,提出了防止地基有害变形的措施,以供参考。     

基坑开挖对非均匀软土地基建筑物影响的现场监测研究

以临近基坑非均匀软土地基建筑物的沉降监测资料为依据,详细分析了场地地质条件、基坑降水和土方开挖等因素对临近建筑物沉降的影响,总结了非均匀软土地基上建筑物沉降的分布特征和变化规律。探讨了建筑物损害与建筑物沉降、墙体倾斜率和基础形式的关系。针对软土地基和砌体结构建筑物,指出了地下水位和基础水平位移监测在建筑物安全性评价中的重要性。     

微环境对流纹岩风化速度的影响

 通过对位于浙江省衢州市南宗孔氏家庙中2个建造于1520年的流纹岩灯台的风化进行研究,不仅得出流纹岩在潮湿环境下的风化速度为0.4～9.7 mm/(100 a),而且发现不同灯台之间、同一灯台的不同部位之间以及同一灯台同一部位不同朝向之间的风化速度都有较大的差异。如：(1) 灯台1和2上圆盘上表面朝北向的风化速度分别为4.3和9.7 mm/(100 a),大于朝南向的风化速度,分别为基点(即未风化点)和2.1 mm/(100 a);而下圆鼓则恰恰相反：灯台1朝西南向和灯台2朝南向的风化速度则是其下圆鼓中最大的(分别为3.08和2.05 mm/(100 a))。据分析,造成这种差异的原因是灯台所处的微环境(如风、降水、太阳辐射等)的不同。(2) 与其他部位相比,两灯台上圆盘插烛孔的风化速度最小,其最大值为1.0 mm/(100 a)。这可能是因为插烛孔内常年积水而隔绝空气所致,可以通过采取改善石灯台风化环境的措施对其进行长期保护。     

A comparison of stochastic process models for definition of design contours

So-called design contour methods are frequently applied for large and complex structures in order to minimize the number of time-consuming structural analyses. These methods are based on first identifying extreme environmental conditions with a given probability of exceedance based on the relevant joint distribution function. These conditions are located along a level surface (i.e. “contour”) in the space of load parameters. As the second step, response analyses are performed for a selection of extreme conditions which are located along this contour. The highest response level which is obtained as a result of these analyses is then applied for design purposes.This approach is based on a representation of the underlying stochastic processes in terms of a sequence of piecewise constant levels. In the present paper, the extreme environmental conditions which are obtained based on such a model are compared to those obtained by instead applying a continuous process model. Furthermore, various alternative and relevant definitions of design contours are compared for the two-component case.In the present analysis, mainly stochastic processes which represent load parameters are considered. However, the approach for identification of level surfaces is of a general nature and can be applied to any types of random vector processes.     

Centrifuge model test on dynamic behavior of group-pile foundation With inclined piles and its numerical simulation

In this paper, dynamic behavior of a grouppile foundation with inclined piles in loose sand has been investigated with centrifuge model tests. The test results are also simulated with elastoplastic dynamic finite element method, in which, not only sectional force of piles, stress of ground, but also deformation of piles are calculated using a three-dimensional elastoplastic dynamic finite element analysis (Code name: DGPILE-3D). The numerical analyses are conducted with a full system in which a superstructure, a pile foundation and surrounding ground are considered together so that interaction between pile foundation and soils can be properly simulated because the nonlinearities of both the pile and the ground are described with suitable constitutive models. Different types of piles, vertical pile or inclined pile, are considered in order to verify the different characteristics of a group pile foundation with inclined piles. The validity of the calculation is verified by the model tests.     

含交叉多裂隙类岩石材料单轴压缩力学性能研究

 以类岩石材料模拟岩体,考虑了主次多裂隙、等长多裂隙两类交叉多裂隙形式,制作含交叉多裂隙试件,对试件进行单轴压缩实验,研究了含交叉多裂隙岩体在单轴压缩下的力学性能。研究表明：含2条交叉裂隙试件强度高于含单一裂隙试件,当裂隙数量超过2条(不含)时,含主次多裂隙试件峰值强度与含单一裂隙试件接近,含等长多裂隙试件的峰值强度及试件破坏所需外力功都低于含单一裂隙试件;次裂隙数量增加对含主次多裂隙试件强度影响不明显,裂隙数量增加对含等长多裂隙试件的强度降低作用非常明显;绝大部分含交叉多裂隙试件峰值强度对应应变低于含单一裂隙试件;含主次多裂隙试件起裂应力高于含单一裂隙试件,大部分含等长多裂隙试件起裂应力低于含单一裂隙试件;含单一裂隙试件破坏面为剪切裂隙,含交叉多裂隙试件破坏面以张拉裂隙为主。     

The debris flight equations

This paper presents a mathematical analysis of the equations of debris flight. In particular the two-dimensional motions of two types of debris are considered—compact and sheet debris. The equations of motion for debris flight are derived in a generalised dimensionless form that reveals the fundamental controlling parameters of the problem. Simplified forms of the equations are then derived for compact and sheet debris, and the large time asymptotic solutions derived for velocities and energies. Numerical solutions of the equations of motion are presented for a range of the controlling dimensionless parameters that are typical of full-scale conditions. The results are compared as far as possible with experimental data. The results for compact debris are well defined and the predicted dimensionless velocities and trajectories are a function of a single dimensionless parameter. For the sheet debris, however, the situation is much more complex, and the results show a level of sensitivity to boundary conditions and the values of the controlling parameters that is typical of chaotic systems. For such objects debris flight can take a number of forms with clockwise, anti-clockwise or no rotation taking place. The resulting dimensionless trajectories and velocities are widely spread. The effect of simulating atmospheric turbulence on the flight of both types of object was also considered, and it was shown that if the gust wind speed during the course of the debris flight is used as the normalising velocity, the variations in trajectory, although noticeable, are not particularly large. A discussion of how this analysis could be used in the design process is then presented, conclusions are drawn and suggestions made for further work.     

社会主义新农村建设中的住宅设计浅析——一次农村住宅项目的分析与总结

在目前社会主义新农村的建设热潮中,住宅是农民最关心的切身问题之一.借着这个形势,建筑师得以介入一次计划提供50套低层独院式农村住宅的项目.通过实地调研,该文重新比较了古农村民居与现代农宅的巨大落差,然后剖析了目前农民住宅存在的若干问题,指出良好的农村住宅建设必须依靠集中的力量来完成,需要建筑师的介入.在本次设计中,建筑师首先梳理了农宅功能,将现代化的城市生活引入新农村住宅设计中来,同时又良好地照顾到农村生产生活的特性,在形式表现上,注入乡土元素,使得农村住宅呈现出一种"二元性"的建筑形式,最后指出了进入到实践环节的农村住宅设计所必须注意的一些问题.     

临时用房的雷电防护探讨

随着社会经济的快速发展、自然灾害的频繁发生等因素,需要搭建的各种临时用房越来越多。但由于临时用房不是永久性的建筑,使用时间有限,由于建设工期紧迫以及建设单位节约建造成本等原因,使其很多方面都不完善,其中的防雷设施往往容易被忽略。临时用房常常搭建在空旷的野外或近水的河边,处于易被雷击的区域。因此,本文针对临时用房的直击雷和雷电波侵入防护进行了探讨,希望能对临时用房的雷电防护起到积极的作用。     

Computational design optimization: A review and future directions

A mathematical model for design optimization of engineering systems is defined. Computational algorithms to treat the model are reviewed and their features are discussed. The attributes of a good algorithm are given. Sequential quadratic programming algorithms that generate and use the approximate Hessian of the Lagrange function to calculate the search direction are the most recent methods. They are the most reliable methods among the available ones. Several other computational aspects, such as robust implementation of algorithms, use of a knowledge base, interactive use of optimization, and use of a database and database management system, are discussed. Recent developments in the field and future directions are presented.     

Torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic half-space

Considering the interactions between an embedded foundation and saturated soil, the torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic medium are analyzed in this paper. Both a rigid foundation and an elastic foundation are considered. Assuming both the side surface and the bottom surface of the foundation are perfectly bonded to soil, the reaction torques that the side soil and bottom soil acting on the foundation can be gained from basic dynamic equations of the poroelastic medium. According to the dynamic equilibrium equations of a foundation under harmonic torque, the torsional vibrations of an embedded cylindrical foundation are presented. Besides, the angular amplitude of the foundation, the equivalent stiffness and damping coefficients of the soil are expressed explicitly. Selected examples are presented to investigate the influence of relevant parameters on the torsional vibrations.     

广义Gibson地基上刚性圆板的扭转特性(英文)

考虑地基为饱和的且下卧基岩,研究了广义Gibson地基上刚性圆板在简谐扭转荷载作用下的动力响应问题。从饱和地基Biot理论出发,建立了剪切模量随深度线性变化的饱和地基动力微分方程,结合扭转振动的特点,通过Hankel变换求解了此微分方程,给出了Hankel变换域内的剪应力和切向位移。然后根据饱和地基与基础接触面处为混合边界条件、饱和地基与基岩接触面处应力和位移连续等边界条件,建立了描述扭转振动的对偶积分方程,借助数学方法求解此对偶积分方程,并给出了基础的动力柔度系数和角位移幅值的表达式。最后通过数值算例研究了地基的非均质性和渗透性对基础扭转特性的影响。