Innovative Sensor and Analyses for Investigating the Effects of Freeze-Thaw on Soil

2011 ◽  
Vol 255-260 ◽  
pp. 4251-4255
Author(s):  
Zhen Liu ◽  
Xin Bao Yu ◽  
Javanni Gonzalez ◽  
Xiong Bill Yu
Keyword(s):  
Time Domain ◽  
Time Domain Reflectometry ◽  
Mechanical And Thermal Properties ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Sensor Performance ◽  
Standard Specimens ◽  
Thawing Processes ◽  
Preliminary Study

Freeze-thaw is a major source of damages for infrastructures located in cold regions. Investigating the effects of freeze-thaw on soil mechanical and thermal properties is important for the design and maintenance of infrastructures such as pavements and pipelines. Most existing research investigates soil behaviors in complete freeze or complete thaw conditions. Tools to assist the determination of freeze-thaw status are currently lacking. In this paper, we introduced the design of an innovative guided electromagnetic wave sensor called Time Domain Reflectometry (TDR) that can non-destructively monitoring the freeze-thaw process in standard specimens of soil and concrete. An analysis algorithm is developed to interpret TDR signals. Compared with the existing technologies, the new method not only accurately determines the various stages in the freezing and thawing processes, but also the degree of freeze-thaw status. This analyses algorithm is also independent of soil types and thus can be widely applied. Experiments were conducted on typical types of soils to validate the sensor performance. With the aid of this new sensor, the effects of the degree of freeze-thaw on soil mechanical properties (such as the modulus, strength and volume change) are determined. The success of our preliminary study indicates the innovative sensor and analyses we developed can be a useful tool for investigating the fundamentals of freeze-thaw effects on geomaterials.

Determining Soil Ice Contents during Freezing and Thawing with Thermo-Time Domain Reflectometry

2015 ◽  
Vol 14 (8) ◽  
pp. vzj2014.12.0179 ◽  
Author(s):  
Zhengchao Tian ◽  
Joshua Heitman ◽  
Robert Horton ◽  
Tusheng Ren
Keyword(s):  
Time Domain ◽  
Time Domain Reflectometry ◽  
Freezing And Thawing

Quantitative, zerstörungsfreie Feuchtemessung in Baustoffen vor Ort mit der Time Domain Reflectometry / Quantitative, non-destructive moisture measurement in building materials on site by time-domain re ectometry

1999 ◽  
Vol 5 (6) ◽  
pp. 609-618
Author(s):  
M. Stacheder ◽  
G. Grassegger ◽  
F. Grüner
Keyword(s):  
Time Domain ◽  
Building Materials ◽  
Salt Content ◽  
Time Domain Reflectometry ◽  
New Method ◽  
Measuring Methods ◽  
Surface Moisture ◽  
Non Destructive ◽  
Floor Cover

Abstract A new commercially available dielectric technique for the non-destructive determination of moisture in building materials based on the principle of 'time-domain reflectometry' (TDR) is presented. TDR measurements on samples of sandstone, brick, concrete and floor cover matched very well with results of conventional moisture measuring methods such as oven-drying or calciumcarbide-technique. The new method showed only a low influence of salt content or surface moisture of the material on the results.

Separation and Determination of the Disturbing Signals in Phase-Sensitive Optical Time Domain Reflectometry (Φ-OTDR)

2015 ◽  
Vol 33 (15) ◽  
pp. 3156-3162 ◽  
Author(s):  
Huijuan Wu ◽  
Shunkun Xiao ◽  
Xiaoyu Li ◽  
Zinan Wang ◽  
Jiwei Xu ◽  
...  
Keyword(s):  
Time Domain ◽  
Time Domain Reflectometry ◽  
Optical Time Domain Reflectometry ◽  
Phase Sensitive ◽  
Optical Time

scholarly journals Time domain reflectrometry measurements using a movable obstacle for the determination of dielectric profiles

2008 ◽  
Vol 6 ◽  
pp. 1-4
Author(s):  
B. Will ◽  
M. Gerding ◽  
S. Schultz ◽  
B. Schiek
Keyword(s):  
Dielectric Constant ◽  
Water Content ◽  
Time Domain ◽  
Measurement Techniques ◽  
Measurement Data ◽  
Time Domain Reflectometry ◽  
Dielectric Measurement ◽  
Effective Dielectric Constant ◽  
Pulse Delay

Abstract. Microwave techniques for the measurement of the permittivity of soils including the water content of soils and other materials, especially TDR (time domain reflectometry), have become accepted as routine measurement techniques. This summary deals with an advanced use of the TDR principle for the determination of the water content of soil along a probe. The basis of the advanced TDR technique is a waveguide, which is inserted into the soil for obtaining measurements of the effective soil permittivity, from which the water content is estimated, and an obstacle, which can mechanically be moved along the probe and which acts as a reference reflection for the TDR system with an exactly known position. Based on the known mechanical position of the reference reflection, the measured electrical position can be used as a measure for the effective dielectric constant of the environment. Thus, it is possible to determine the effective dielectric constant with a spatial resolution given by the step size of the obstacle displacement. A conventional industrial TDR-system, operating in the baseband, is used for the signal generation and for the evaluation of the pulse delay time of the obstacle reflection. Thus, a cost effective method for the acquisition of the dielectric measurement data is available.

scholarly journals Determination of ice-shelf bottom melting by time-domain reflectometry

1993 ◽  
Vol 39 (132) ◽  
pp. 353-356
Author(s):  
K. Grosfeld ◽  
N. Blindow
Keyword(s):  
Transmission Lines ◽  
Time Domain ◽  
High Reliability ◽  
Melting Rate ◽  
Time Domain Reflectometry ◽  
Ice Shelf ◽  
Wave Forms ◽  
A New Technique ◽  
Tape System

AbstractFor our work in the Filchner-Ronne Ice Shelf Programme (FRISP), we have developed a new technique for measuring the bottom-melting rate with high reliability. The method is based on time-domain reflectometry (TDR) measurements of transmission lines inserted into melt holes. The TDR-data are digitally recorded on magnetic tape. System resolution has been estimated at 0.2 m. Hence, re-measuring after 1 year gives an accuracy of 10% for melting rates of 2m a-1. Two transmission lines for TDR measurements were installed during the German FRIS Expedition 1989–90. This paper describes the design of the system. Examples of recorded wave forms are given.

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