登录查看更多内容

How can you investigate subsurface conditions using geophysical methods?

由人工智能和领英社区提供技术支持

As a structural engineer, you may need to assess the subsurface conditions of a site before designing or retrofitting a building. This can help you identify potential hazards, such as soil liquefaction, fault rupture, or ground shaking, that could affect the stability and performance of your structure. One way to investigate the subsurface conditions is by using geophysical methods, which are non-invasive techniques that measure the physical properties of the soil and rock layers. In this article, you will learn about some of the common geophysical methods and how they can help you evaluate the seismic risk of a site.

此文章中的业界达人

由社区从 3 条内容中精选。了解更多

Nancy House

Past President 2018-2019 at SEG

1 Seismic methods

Seismic methods are based on the principle that seismic waves, which are generated by natural or artificial sources, travel at different speeds and reflect or refract at the boundaries of different materials. By measuring the travel time and amplitude of the seismic waves, you can infer the depth, thickness, and stiffness of the subsurface layers. There are two main types of seismic methods: surface wave methods and refraction methods. Surface wave methods use the waves that propagate along the surface of the ground, such as Rayleigh or Love waves, to estimate the shear wave velocity and the dynamic properties of the soil. Refraction methods use the waves that penetrate the subsurface and bend at the interfaces of different materials, such as P or S waves, to estimate the compressional wave velocity and the depth of the bedrock.

添加您的观点

Nancy House

Past President 2018-2019 at SEG
(已编辑)
举报内容
Reflection seismic method relies on compressional waves that reflected at boundaries between layers with different properties. The method has evolved to utilizing reflected concerted waves to extract additional rock properties. .

已翻译

赞

2 Electrical methods

Electrical methods are based on the principle that the electrical resistivity or conductivity of the subsurface varies depending on the type, porosity, saturation, and salinity of the soil and rock. By applying an electric current between two electrodes and measuring the potential difference between two other electrodes, you can determine the apparent resistivity of the subsurface. By changing the spacing and configuration of the electrodes, you can obtain different depths of investigation. Electrical methods can help you identify the water table, the presence of clay or sand layers, or the location of faults or fractures.

添加您的观点

Nancy House

Past President 2018-2019 at SEG
举报内容
As with all geophysical methods the key is understanding what is being measured and where the measurements need to be located. Interpreting the results is accomplished by understanding the physical response of the rocks to electrical stimulation.

已翻译

赞

加载更多内容

3 Magnetic methods

Magnetic methods are based on the principle that the magnetic field of the earth is influenced by the magnetic properties of the subsurface. By measuring the variations in the intensity, direction, or gradient of the magnetic field, you can detect the anomalies caused by the presence of magnetic materials, such as iron ores, basalt, or magnetite. Magnetic methods can help you map the geologic structure, the depth of the basement, or the distribution of volcanic rocks.

添加您的观点

4 Gravity methods

Gravity methods are based on the principle that the gravitational attraction of the earth is affected by the density and distribution of the subsurface. By measuring the variations in the gravity field, you can infer the mass and shape of the subsurface features. Gravity methods can help you estimate the thickness of the sedimentary layers, the location of cavities or voids, or the density contrast of the bedrock.

Geophysical methods are powerful tools that can provide valuable information about the subsurface conditions of a site. However, they also have limitations, such as resolution, accuracy, or interference from external sources. Therefore, it is important to select the appropriate method or combination of methods for your specific project, and to calibrate and interpret the results with other geotechnical data, such as boreholes, cone penetration tests, or laboratory tests.

添加您的观点

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

添加您的观点

Structural Engineering

+ 关注

给文章评分

我们借助人工智能创建了此文章。您认为这篇文章怎么样？

很棒不太好

举报此文章

查看全部

How can you investigate subsurface conditions using geophysical methods?

1

2

3

4

5

1 Seismic methods

2 Electrical methods

3 Magnetic methods

4 Gravity methods

5 Here’s what else to consider

Structural Engineering

给文章评分

感谢您的反馈

更多Structural Engineering相关文章

更多相关阅读内容

How can you investigate subsurface conditions using geophysical methods?

1

2

3

4

5

1 Seismic methods

2 Electrical methods

3 Magnetic methods

4 Gravity methods

5 Here’s what else to consider

Structural Engineering

给文章评分

感谢您的反馈

查看其他技能