岩土工程中水文地质问题的危害性

岩土工程施工中会受到水文地质的影响,往往被工作人员忽视,导致一系列问题产生。为了保证岩土工程的质量,必须就水文地质问题对岩土工程的危害性进行分析研究,提出有效解决策略,以提高工程质量,保证工程安全。     

地下工程环境岩土工程问题研究与认识

优势面分析作为环境岩土工程与地质灾害研究的理论和方法,可为地下工程稳定性评价、设计和施工提供基础依据。将该理论运用于三峡、黑山峡、大柳树等重大水利工程,铁路国梁山隧道、高速公路老山隧道等重要交通干线工程,苏南核电站和蓄能电站、南京市地铁等工程中。通过对工程的选址定位、安全评价、设计施工等工作中的认识和体会,就研究目标（三个稳定性和突水分析）、问题关键（找优势面、优势层）、支护设计方法（四类）、支护和防水设计的人地谐调原理（针对性、地质工程原理、顺应自然）等多方面问题作以分析和研讨。     

Advanced performance in geotechnical engineering using tomography analysis

This paper presents the technique to demonstrate reliable two-dimensional (2-D) tomography of near-surface soil through multichannel analysis of surface wave (MASW) method. The MASW method is used as seismic method for determining the shear wave velocity profile of near-surface soil with better performance. Normally, this method represents one-dimensional (1-D) soil layer profile to delineate anomalous subsurface materials and detect soil characteristics in geotechnical investigations. Conventionally, the MASW method is able to represent depth corresponding shear wave velocity through 1-D representation. In this paper, this method is improved through representation of depth and distance versus shear wave velocity profile using 2-D tomography analysis in geotechnical investigations. The outcomes of the newly developed method are more reliable and informative in comparison to the outcome of the conventional MASW method. The significance of this research is incorporating advanced tomography technique with MASW method to obtain 2-D tomography of geotechnical characteristics with consistency.     

吉林省岩土工程勘察问题探讨

文章根据岩土工程强制性条文要求,论述了工程勘察存在地下水类型、抗浮水位确定、场地类别和液化判别等实际问题,并对示范性文本作了某些补充分析及探讨,对于深化勘察内容有较大指导意义。     

岩土工程勘察常见质量问题及改进建议

综合归纳了岩土工程勘察工作从野外勘察施工、勘察成果分析与评价、地基基础方案分析到报告编制的各个环节所出现的常见质量问题,并分析探讨其产生的根源,提出了提高勘察成果质量的建议。     

南通市主要环境岩土工程问题初探

随着南通经济的飞速发展和城市化进程的加快,引发了一系列环境岩土工程问题,主要有地面沉降、江岸坍塌、软土变形、砂土液化、水土污染等,影响了南通市社会和经济的可持续发展。分析了南通市的主要环境岩土工程问题,提出了相应的防治对策建议。     

岩土工程CAD系统建模技术的研究

论述了在开发CAD系统中引入面向对象的设计思想的优点,结合开发岩土工程CAD系统实例,对其中的关键技术--系统建模进行了分析,并就建立一般的系统模型技术进行了探讨。同时,给出了必要的代码,提供给相关程序开发者借鉴。     

A finite element approach to solve contact problems in geotechnical engineering

This paper presents a finite element approach to solve geotechnical problems with interfaces. The behaviours of interfaces obey the Mohr–Coulomb law. The FEM formulae are constructed by means of the principle of virtual displacement with contact boundary. To meet displacement compatibility conditions on contact boundary, independent degrees of freedom are taken as unknowns in FEM equations, instead of conventional nodal displacements. Examples on pressure distribution beneath a rigid strip footing, lateral earth pressure on retaining walls, behaviours of axially loaded bored piles, a shield‐driven metro tunnel, and interaction of a sliding slope with the tunnels going through it are solved with this method. The results show good agreement with analytical solutions or with in situ test results. Copyright © 2005 John Wiley & Sons, Ltd.     

Use of evolutionary computing for modelling some complex problems in geotechnical engineering

In this paper, the feasibility of using evolutionary computing for solving some complex problems in geotechnical engineering is investigated. The paper presents a relatively new technique, i.e. evolutionary polynomial regression (EPR), for modelling three practical applications in geotechnical engineering including the settlement of shallow foundations on cohesionless soils, pullout capacity of small ground anchors and ultimate bearing capacity of pile foundations. The prediction results from the proposed EPR models are compared with those obtained from artificial neural network (ANN) models previously developed by the author, as well as some of the most commonly available methods. The results indicate that the proposed EPR models agree well with (or better than) the ANN models and significantly outperform the other existing methods. The advantage of EPR technique over ANNs is that EPR generates transparent and well-structured models in the form of simple and easy-to-use hand calculation formulae that can be readily used by practising engineers.     

浅部厚层粉性土分层中的一些问题

上海市沿江地区浅部粉性土具有厚度大、物理力学性质复杂多变的特征.文章就该层土的岩土工程分层进行专门讨论.     

Implementing statistical fitting and reliability analysis for geotechnical engineering problems in R

Reliability analysis and multivariate statistical fitting are valuable techniques that enhance the scientific basis of regulatory decisions in geotechnical problems. This study introduces the use of several R packages specifically developed to assist risk assessors in their geotechnical projects. Firstly, the fitting of parameterised models either to the distribution of observed samples or to characterise the dependence structures among variables, or both is presented. Secondly, the most popular reliability analysis methods, such as the first- and second-order reliability methods and the random sampling simulation method, are implemented in R. The efficiency of implementing these classical approximation methods is demonstrated through two example problems.     

地铁工程勘察的抽水试验设计和施工技术

本文结合广州地铁三号线岩土工程勘察的管理，对抽水试验的设计和施工技术进行了较全面的论述，指出只有合理地进行抽水试验设计和严格地控制抽水试验施工质量，才能取得准确而可靠的试验结果。     

西安市固体废弃物卫生填埋场建设中的环境岩土工程问题研究

人与环境的和谐共处是当今社会可持续发展的重要内容,面对城市固体废弃物激增所带来的人与环境之间的各种问题,卫生填埋法作为最广泛也是最彻底的固体废弃物处理方法得到了越来越多的关注和研究。卫生填埋场的建设与环境岩土工程领域内的诸多方面密切相关,针对卫生填埋场的建设中涉及到的环境岩土工程问题,在依据已有资料概括介绍国内外相关发展现状的同时,结合西安地区的特点,在填埋场场址和类型选择、废弃物工程性质指标、填埋场防渗处理、填埋场沉降计算和边坡稳定这5个方面对西安地区城市固体废弃物卫生填埋场建设中的环境岩土工程问题进行了论述,提出了相应建议,展望了研究方向。     

一种解岩土工程变形体-刚体接触问题的有限元法

大多数的岩土工程问题都会涉及到岩土体-结构之间的相互作用,它们之间界面的合理模拟对计算结果有重要的影响。目前常用的Goodman节理单元、Desai薄层单元等虽然简单好用,但也存在着明显的缺陷。相比之下,作为接触问题计算,可更为合理地模拟接触面的力学行为。针对变形体-刚体这种特殊的接触问题,应用变形体的虚功原理建立了相应的虚功方程,在此基础上得出有限元计算公式,并建立了弹塑性接触问题有限元计算的实现方法。通过对刚性条形基础基底压力分布和刚性挡墙土压力分布等算例的计算,验证了该法的正确性和求解工程问题的有效性。     

拉萨岩土工程勘察回顾

本文论述勘查区地质、水文地质条件和工程地质特征.通过岩土工程勘察和实地调查,该区一是地形险峻、地质环境复杂.二是气象、水文条件多变.在极端恶劣的环境完成4项优秀工程地质勘察成果报告,关键在于岩土工程勘察过程中进行了实地调研和资料收集等工作,才能取得较理想的效果.     

Tracing the equilibrium path by dynamic relaxation in materially nonlinear problems

Material non-linearity in non-associated high friction materials exhibiting post-peak softening such as granular materials poses a great problem in solving the non-linear differential equations. In this regard, a dynamic relaxation (DR) family of solutions provides a very strong tool to solve. In this paper, the DR method is evaluated from the viewpoint of its ability to trace the whole equilibrium curve in the load–displacement (stress–strain) space. In the case of material non-linearity, usually there is a snap-through. This problem has been handled in three ways: (1) load control with a real time dynamic solution at post-peak, (2) direct displacement control and (3) arc-length control. These three methods of non-linear equilibrium path tracing are critically evaluated with respect to their speed of convergence, accuracy of the solution and states of unequilibrium. Finally, the results of multi-element FEM simulations of a bearing capacity test of a strip footing on sand carried out to validate the DR methods are presented.     

An adaptive high-dimensional model representation method for reliability analysis of geotechnical engineering problems

In this study, a new reliability analysis method was developed based on the adaptive high-dimensional model representation (HDMR) and applied to geotechnical engineering problems. For practical problems requiring finite element (FE) analysis or other numerical methods to evaluate system responses such as stresses and deformations, an efficient and accurate metamodeling technique is needed because it is not efficient or straightforward to directly adopt the conventional sampling-based or gradient-based reliability analysis approaches. In this work, an adaptive metamodeling approach was created and studied based on the HDMR framework and augmented radial basis functions (ARBFs). In this adaptive ARBF-HDMR technique, a simple and inexpensive first-order ARBF-HDMR metamodel was first constructed to explicitly express a performance function, and an alternate first-order reliability method (FORM) was applied to locate the design point and compute the reliability index. A local window was then defined such that additional sample points were generated and a higher-order HDMR component function was created using ARBF and added to the existing ARBF-HDMR metamodel. The accuracy of the ARBF-HDMR metamodel was improved through this adaptive process, especially in the region surrounding the design point. One mathematical and four geotechnical engineering problems were studied and solved using the proposed adaptive ARBF-HDMR approach. The proposed method was found to be capable of obtaining accurate reliability indices within a few iterations in all test problems.     

图像测量技术在岩土工程CT图像定量分析中的应用

首先对计算机层析成像技术(CT技术)原理进行了简单的介绍,基于图形图像处理技术,引入了数学形态学中图像平移、反射、腐蚀、膨胀等运算方法,基于定义的兴趣域边界提取算法和形状因子实现了其几何测量和空间描述,定量分析了CT图像兴趣域的空间物理特性.该方法异于以往数学建模的思路,而是借用数学形态学中空间几何描述的思想,以实现对岩土体中的天然缺陷及其演化过程进行合理刻画.该项工作对于推动岩土工程CT图像定量化描述具有一定意义.     

Electrical conductivity problems associated with time-domain reflectometry (TDR) measurement in geotechnical engineering

The effect of electrical conductivity (EC) of a dielectric material on its TDR-measured dielectric constant ε_a (called the apparent dielectric constant) was investigated both theoretically and experimentally. The effect of EC on the apparent dielectric constant ε_a was more pronounced at low frequency of the electromagnetic pulse applied to measure ε_a. The assumption of neglecting electrical losses in measuring the dielectric constant by TDR to represent ε_r was not valid for dielectric materials containing free charges, such as electrolyte solutions, bentonite clay, and saline soils. A theory is proposed to separate the real part of the dielectric constant ε_r from the TDR-measured ε_a in lossy dielectrics. An EC - ε_r relationship can be developed that would provide ε_a (=ε_r) at EC = 0 to be used to determine soil-water contents in conductive soils. Na-bentonite mixed with distilled water resulted in considerable magnitude of bulk EC due to the adsorbed cations on the surface of the particles. This EC caused energy loss of the TDR pulse that depended on the length of the probe rod. For a 4.5 cm long probe, the reflected TDR waveform was completely attenuated for EC between 3.05 dS m⁻¹ and 3.72 dS m⁻¹. The waveforms generated in this range of EC were not suitable for analysis by TDR-support software for dielectric constant. With the adsorbed cations, Na-bentonite behaved as a lossy or dispersive material. This revised version was published online in July 2006 with corrections to the Cover Date.