Non-invasive time domain reflectometry probe for transient measurement of water retention curves in structured soils

Mu, Qingyi; Zhan, Liang Tong; Lin, Chang‐Ching; Chen, Yunmin

doi:10.1016/j.enggeo.2019.105335

Cited by 13 publications

(4 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Soil water contents at the sampling locations were monitored from April to November in 2018 using the time domain reflectometry [19,20] and shown in Figure 2. This period covers both the dry and wet seasons in Yan'an.…”

Section: Test Soilmentioning

confidence: 99%

Effects of In-Situ Drying–Wetting Cycles on the Stress-Dependent Water Retention Behavior of Intact Loess

Shi

et al. 2023

Advances in Civil Engineering

View full text Add to dashboard Cite

Understanding the effects of in-situ drying–wetting pattern on the stress-dependent water retention curve of intact loess is vital for addressing geotechnical problems in loess regions. The principal objective of this study is to investigate the influence of in-situ drying–wetting on the stress-dependent water retention behavior of intact loess. To meet this objective, six drying–wetting tests were carried out using a suction- and stress-controlled pressure plate extractor. Intact loess was sampled from three different depths: 1.0, 3.0, and 5.0 m. For specimens from each depth, two vertical net stresses (i.e., 0 and 50 kPa) were applied prior to the drying–wetting cycle. Experimental results revealed that the in-situ drying–wetting pattern greatly affected various aspects of the water retention behavior, particularly the hysteresis. The hysteresis of the specimen from 5.0 m is about 82% and 77% larger than that of the specimens from 1.0 and 3.0 m, respectively. This is because the specimen from 5.0 m has some large-size pores (i.e., >400 μm), which were not found in specimens from 1.0 and 3.0 m. These large-size pores enhance pore nonuniformity and hence the hysteresis. Furthermore, specimens from different depths consistently showed a reduction of hysteresis when the stress was increased from 0 to 50 kPa. The reduction is the most significant for a specimen from 5.0 m due to the collapse of large-size pores under compression.

show abstract

Section: Test Soilmentioning

confidence: 99%

Effects of In-Situ Drying–Wetting Cycles on the Stress-Dependent Water Retention Behavior of Intact Loess

Shi

et al. 2023

Advances in Civil Engineering

View full text Add to dashboard Cite

show abstract

“…Its ability to collect soil water content data over a large area with high accuracy is very relevant to the needs of precision farming. The Gravimetric [5], Conductive [52], Capacitive [53], and TDR [16][17][18][19] methods are commonly operated as the invasive method. In the plantation case, when a vegetation layer covers the soil surface, the invasive method is less support in collecting measurement data for a large area.…”

Section: Resultsmentioning

confidence: 99%

“…The wave propagation phenomenon is generally used as a basic concept in the remote sensing method. These remote sensing methods include satellite imaging [8][9][10], Synthetic Aperture Radar (SAR) [11][12][13][14], radiometry [15], Time domain reflectometry (TDR) [16][17][18][19] and Ground Penetrating Radar (GPR) [20][21][22][23][24][25][26]. The measurement result from a contact or invasive sensor such as a TDR is limited to a certain point in representing the soil water content.…”

Section: Introductionmentioning

confidence: 99%

Soil Water Content Estimation With the Presence of Vegetation Using Ultra Wideband Radar-Drone

Pramudita

Wahyu²,

Rizal

et al. 2022

IEEE Access

View full text Add to dashboard Cite

Radar-drone system is potentially implemented as a method for collecting the soil water content of a large area. Vegetation that may covers the soil surface affects the detection results of soil water content using radar system in plantation areas. Vegetation will influence the propagation mechanism of radar waves, therefore, a method to overcome this effect is needed. The method to compensate the effect of vegetation based on a transmission line model is then proposed in this paper. The transmission line model is used as the concept for transforming the measured reflection coefficient under the vegetation effect to the ground reflection coefficient value. Experiments were carried out by taking a case studies on tea plantations. The tea plant becomes a vegetation layer which its effect needs to be considered on the detection of soil water content. An ultra-wideband radar system with a frequency range of 500 MHz -3 GHz is proposed in this study. The radar is integrated to hexacopter drone for scanning the tea plantation areas. The radar-drone system flight with a constant elevation from ground level. The experimental results show that the proposed method is able to improve the detection results of soil water content using radar with an accuracy of 96%. The radar-drone performance in detecting soil water content is suitable for precision farming purposes.

show abstract

“…Therefore, it cannot be applied in a large area. TDR method, neutron method and gas content volume method also have the same disadvantages ( Mu et al., 2020; Schafer & Beier, 2020 ). The remote sensing method can be used to estimate the regional moisture content (Ainiwaer et al., 2020), but it can only measure the shallow part of the soil.…”

Section: Introductionmentioning

confidence: 99%

Soil water content estimation using ground penetrating radar data via group intelligence optimization algorithms: An application in the Northern Shaanxi Coal Mining Area

Fan

et al. 2020

Energy Exploration & Exploitation

View full text Add to dashboard Cite

The determination of quantitative relationship between soil dielectric constant and water content is an important basis for measuring soil water content based on ground penetrating radar (GPR) technology. The calculation of soil volumetric water content using GPR technology is usually based on the classic Topp formula. However, there are large errors between measured values and calculated values when using the formula, and it cannot be flexibly applied to different media. To solve these problems, first, a combination of GPR and shallow drilling is used to calibrate the wave velocity to obtain an accurate dielectric constant. Then, combined with experimental moisture content, the intelligent group algorithm is applied to accurately build mathematical models of the relative dielectric constant and volumetric water content, and the Topp formula is revised for sand and clay media. Compared with the classic Topp formula, the average error rate of sand is decreased by nearly 15.8%, the average error rate of clay is decreased by 31.75%. The calculation accuracy of the formula has been greatly improved. It proves that the revised model is accurate, and at the same time, it proves the rationality of the method of using GPR wave velocity calibration method to accurately calculate the volumetric water content.

show abstract

Non-invasive time domain reflectometry probe for transient measurement of water retention curves in structured soils

Cited by 13 publications

References 32 publications

Effects of In-Situ Drying–Wetting Cycles on the Stress-Dependent Water Retention Behavior of Intact Loess

Effects of In-Situ Drying–Wetting Cycles on the Stress-Dependent Water Retention Behavior of Intact Loess

Soil Water Content Estimation With the Presence of Vegetation Using Ultra Wideband Radar-Drone

Soil water content estimation using ground penetrating radar data via group intelligence optimization algorithms: An application in the Northern Shaanxi Coal Mining Area

Contact Info

Product

Resources

About