QUAKE/W 2007：地震工程模拟与地质技术的动态建模方法

需积分: 10 177 浏览量更新于2024-07-19 收藏 3.46MB PDF 举报

《QUAKE/W 2007工程手册：地震动力模拟方法与工程实践》本手册详细介绍了QUAKE/W 2007这一在地基土木工程领域广泛应用的工具，专用于模拟地震对地基问题的影响。QUAKE/W是一款动态模拟软件，旨在提供一种工程方法论，帮助工程师理解和预测地震作用下的结构响应，特别关注斜坡稳定性分析（slope/w功能）。第1章首先概述了关键议题，包括： 1.1 **关键问题**：着重讨论了地震分析中的核心挑战，如如何准确处理地震产生的惯性力，以及不同类型土壤（如松散的收缩性砂土和密实的膨胀土）的行为特征。 1.2 **惯性力**：阐述了在地震过程中，如何计算和考虑物体的动态运动，惯性力在结构响应中起着至关重要的作用。 1.3 **细粒土行为**：区分了不同类型的细粒土，探讨了它们在地震时的蠕变、滑动和整体变形特性，这些对地震破坏程度有显著影响。 1.4 **永久变形**：强调了地震可能导致的地面长期变形，这可能对基础设施的耐久性和设计要求产生深远影响。 1.5 **结论性评论**：总结了本节的主要观点，强调了理解地震动力学和使用QUAKE/W进行模拟在工程实践中的重要性。第二章深入探讨了数值建模的概念、目的和实施步骤： 2.1 **简介**：引出了数值建模在地震分析中的地位，它如何帮助工程师做出决策。 2.2 **什么是数值模型？**：解释了数值模型是通过数学和计算机技术，将复杂的物理过程简化为可计算的形式，以便预测工程系统的行为。 2.3 **地质工程中的建模**：讲述了在地基分析中如何构建和应用QUAKE/W模型，包括考虑土壤特性、边界条件和荷载情况。 2.4 **建模的原因**：强调了数值建模的重要性，包括提供定量预测、比较不同设计选项以及识别决定性参数。 2.5 **理解物理过程**：指出通过建模可以揭示地震作用下的土体内部动态过程，有助于工程师更好地掌握潜在风险和优化设计策略。通过阅读《QUAKE/W 2007工程书》，读者将获得深入理解地震对地基工程影响的专业知识，并掌握如何利用这款工具进行有效的模拟和分析，确保结构安全，尤其是在斜坡稳定性的评估中。该手册不仅适用于理论研究，也适用于实际项目的设计和风险评估工作中。

Chapter 1: Introduction QUAKE/W

Page 6

Figure 1-4 Tests on dry sand (after Gu et al. 2002)

Figure 1-5 Tests on dry sand (after Gu et al. 2002)

An important point is that the sudden loss in strength and the resulting liquefaction

can occur under monotonic load – not just cyclic loading.

100

150

200

250

300

0 50 100 150 200 250 300

Effective normal stress p'(kPa)

Shear stress q ( kPa )

Loose

Very loose

0.72

0.74

0.76

0.78

0.80

0.82

0.84

0.86

0.88

0.90

0 50 100 150 200 250 300

Effective normal stress ( kPa )

Void ratio e

Very loose

Loose

Collapse point

QUAKE/W Chapter 1: Introduction

Page 9

shows why the initial static stress state is so important and why early researchers

recognized the need for introducing corrections in the cyclic stress approach.

1.4 Permanent deformation

When there is a zone of soil in a soil structure that has experienced a sudden

strength loss, there will be some stress adjustment and re-distribution. Zones that

have lost their strength will share their excess load with regions that have not

undergone the strength loss. The stress re-distribution will continue until the

structure has once again reached a point of equilibrium. If the strength loss is so

great that the earth structure cannot re-establish equilibrium, the entire structure

will collapse, often with catastrophic consequences. If, however, the structure can

find a new point of equilibrium, the stress re-distribution will be accompanied by

permanent deformations. The chief engineering issue then becomes to determine

how the permanent deformation affects the serviceability of the structure. The

question is whether the structure is still functional or can it be repaired to again be

functional or is the deformation so severe that the structure can no longer be used

for its intended purpose?

There is considerable field evidence as summarized by Gu et al. (1993) that much

of the stress re-distribution and the accompanying permanent deformation takes

place after the earthquake shaking has stopped. If there is a failure, the failure is

delayed by minutes or even hours and for this reason the associated deformation is

referred to as post-earthquake deformation.

An extremely important implication of the delayed movement and failure is that

the deformations are actually driven by static forces – not dynamic forces. The

dynamic forces cause the generation of the excess pore-pressures, but the

damaging deformations are driven by static gravitational forces. This has important

numerical modeling implications. This being the case, a QUAKE/W dynamic

analysis can be used to estimate the generation of excess pore-pressures, but a

QUAKE/W analysis is not required to estimate the permanent deformation. The

permanent deformation can be modeled with a static software product like

SIGMA/W.

Modeling the stress re-distribution should ideally include a strain-softening

constitutive relationship to simulate the strength loss. These types of numerical

algorithms have been developed and used to study the post-earthquake re-

distribution. Gu (1992), for example, developed a strain-softening model as part of

his Ph.D. dissertation for analyzing the post-earthquake stress re-distribution and

Chapter 1: Introduction QUAKE/W

Page 10

was successful in obtaining good agreement between the model predictions and the

observed field behavior at two sites. One was the post-earthquake deformation

analysis of the Wildlife Site in California (Gu et al. 1994) and the other was the

analysis of the progressive failure that occurred at the Lower San Fernando Dam in

California (Gu et al. 1993).

SIGMA/W has a stress re-distribution algorithm which can be used in conjunction

with QUAKE/W results. The SIGMA/W method uses an elastic-plastic

constitutive model and simply re-distributes the excess stress where the stress state

exceeds the soil strength. The procedure can be quite effective even though it

does not follow a prescribed strain-softening path. The premise is that somehow

there was a strength loss and consequently there is a need to re-distribute the

stresses. Stated another way, the SIGMA/W procedure gives the correct end point

but not necessarily the correct path to the end point.

The analyses of the San Fernando Dams described in the QUAKE/W detailed

examples demonstrate that the SIGMA/W approach together with the QUAKE/W

results can be effective in investigating the post-earthquake deformation that may

be associated with liquefaction even though it is not a completely rigorous

approach.

In version 7.1, SIGMA/W also has a “dynamic deformation” analysis that will

consider incremental stresses between saved QUAKE/W time steps as a driving

force for permanent deformation if the chosen constitutive model allows for some

plastic deformation based on stress-redistribution.

1.5 Concluding remarks

Conceptually, the issues as they relate to dynamic analyses, liquefaction, cyclic

mobility and permanent deformation are now fairly well understood. GeoStudio

now has all the components to examine all these aspects. Good illustrations of

this are available in the QUAKE/W detailed examples. The San Fernando Dam

Case Histories, for example, involve seepage analyses with SEEP/W, stability

analyses with SLOPE/W, dynamic analyses with QUAKE/W and post-earthquake

deformation analyses with SIGMA/W.

剩余246页未读，继续阅读

深荷露明

粉丝: 0
资源: 1

QUAKE/W 2007：地震工程模拟与地质技术的动态建模方法

GeoStudio sigma/w engineering book

OGata control engineering book

chaos-engineering-book:混沌工程-docker source code

data-engineering-book:在数据工程领域积累的知识和经验

Security Engineering — The Book(The Second Edition)

2007_Book_ReliabilityEngineering.pdf

the-engineering-managers-booklist:面向或渴望管理软件工程师领导团队的人员的书籍

petroleum production engineering (elsevier, 2007)

data_engineering_on_gcp_book:一本书介绍了如何使用Google Cloud Platform建立和维护数据工程基础架构

is software engineering really engineering?

最新资源