Net load–displacement estimation in soil-nail pullout tests

Seo, Hyungjoon; Pelecanos, Loizos; Kwon, Young Sam; Lee, In Mo

doi:10.1680/jgeen.16.00185

Cited by 11 publications

(6 citation statements)

References 6 publications

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“…Beloni et al (2017) conducted pullout tests with 12 nails without reinjection in a mature gneissic residual soil composed of sandy clay, located in Viçosa -MG (Brazil), obtaining values between 47 kPa and 82 kPa. Seo et al (2017) performed field pullout tests to analytically determine the shear behavior between the soils and grout, especially the soil-dilation effect that occurs during shearing. For this study, three experimental fields with different soil types were selected: colluvial soil, weathered granite soil, and fill soil.…”

Section: Values Of Q Smentioning

confidence: 99%

“…According to Seo et al (2017), the results for the colluvial soil (classified by the Unified Soil Classification System -USCS -as ML) showed values of q s that varied from 96 to 120 kPa. In the weathered granite soil (USCS -SM), the pullout resistance observed ranged from 128 to 160 kPa, and, for the fill soil (USCS -SC), the average value of q s was approximately 72 kPa.…”

Section: Values Of Q Smentioning

confidence: 99%

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Pullout Testing of Soil Nails in Gneissic Residual Soil

Arêdes¹,

Marques²,

Oliveira³

2020

S&R

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Soil nailing has proved to be an efficient and cost-effective stabilization technique, consisting in installing passive reinforcement in the soil that provides the material with tensile and shear strengths. The fundamental parameter in analyzing the mechanical behavior of this type of structure is the frictional resistance of the soil-nail interface, denominated q s . This paper presents the results of pullout tests performed on a slope located on the campus of the Federal University of Viçosa, in Viçosa-MG, Brazil. Drilling boreholes enabled the identification of four different types of soil with predominant composition of fine sand and silt, all characterized as a gneissic residual soil. Different lengths and methodologies were studied in the pullout tests with the aim of assessing the impact these factors have on shear strength. The values of q s obtained in the tests were similar to the ones reported by other authors. Even when running tests with low pressures, the results showed that the first grouting reinjection stage was able to provide a significant gain in the pullout resistance of the nails. Another point of observation was that, even though there are reasonable estimated values of q s in the literature, the conduction of pullout tests is essential for the confirmation of the values to be used in each situation.

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Section: Values Of Q Smentioning

confidence: 99%

Section: Values Of Q Smentioning

confidence: 99%

Pullout Testing of Soil Nails in Gneissic Residual Soil

Arêdes¹,

Marques²,

Oliveira³

2020

S&R

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“…Studies have been conducted to measure roughness in geotechnical engineering. The shear strength between soil and structure is also affected by the roughness (Seo et al (2012), Seo et al (2014) [15,16]) Therefore, it was considered in the design of structure and development of geotechnical structure (Seo et al (2017), [17,18]). Lee and Juang (1991) [7] measured the roughness profile of rock joints using a laser displacement meter (LDM) and a linear variable differential transformer (LVDT).…”

Section: Introductionmentioning

confidence: 99%

3D Roughness Measurement of Failure Surface in CFA Pile Samples Using Three-Dimensional Laser Scanning

Seo

2021

Applied Sciences

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The bearing capacity of CFA (Continuous Flight Auger) pile is not able to reach the design capacity if proper construction is not performed due to the soil collapse at the bottom of the pile. In this paper, three pile samples were prepared to simulate the bottom of the CFA pile: grouting sample; mixture of grouting and gravel; mixture of grouting and sand. The failure surfaces of each sample obtained by a uniaxial compression tests were represented as a three-dimensional point cloud by three-dimensional laser scanning. Therefore, high resolution of point clouds can be obtained to simulate the failure surfaces of three samples. The three-dimensional point cloud of each failure surface was analyzed by a plane to points histogram (P2PH) method and a roughness detection method by kernel proposed in this paper. These methods can analyze the global roughness as well as the local roughness of the three pile samples in three dimensions. The roughness features of the grouting sample, the mixed sample of grouting and sand, and the mixed sample of grouting and gravel can be distinguished by the sections where points of each sample are predominantly distributed in the histogram of the proposed method.

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“…This instrumentation scheme offers very useful but discrete data points (Lehane et al 1993). Data from appropriately monitored pile load tests can provide a means to assess the behaviour of the pile and develop pile behaviour models (Comodromos & Bareka 2009) such as load transfer curves (Ménard 1963;Butterfield & Banergee 1971;Kraft, Ray & Kakaaki 1981;Frank & Zhao 1982;Poulos 1989;Lee 1993;Klar et al 2006;Abchir et al 2015;Seo et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Distributed Fiber Optic Sensing of Axially Loaded Bored Piles

Pelecanos

Soga

Elshafie

et al. 2018

J. Geotech. Geoenviron. Eng.

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Instrumented pile tests are vital to establish the performance of a pile and validate the assumptions made during initial design. Conventional instrumentation includes vibrating wire strain gauges and extensometers to measure the change in strain or displacements within a pile. While these strain and displacement gauges are very accurate, they only provide strain/displacement readings at discrete locations at which they are installed. It is therefore common to interpolate between two consecutive points to obtain the values corresponding to the data gaps in between; in practice, these discrete instrumented points could be tens of Manuscript Click here to download Manuscript Pelecanos_et_al_Manuscript_7.2.docx 2 meters apart, at depths corresponding to different soil layers, and hence simple interpolation between the measurement points remains questionable. The Brillouin Optical Time Domain Reflectometry fibre optic strain sensing system however is able to provide distributed strain sensing along the entire length of the cable, enabling the full strain profile to be measured during a maintained pile load test. The strain data can also be integrated to obtain the displacement profile. In this paper, three case studies are presented where the performance of three concrete bored piles in London is investigated using both conventional vibrating wire strain gauges and distributed fibre optic strain sensing during maintained pile load tests which enabled comparisons to be made between the two instrumentation systems. In addition, finite element analyses were conducted for the three piles and it was found that the ability to measure the full strain profiles for each pile is highly advantageous in understanding the performance of the pile and in detecting any abnormalities in the pile behaviour.

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Net load–displacement estimation in soil-nail pullout tests

Cited by 11 publications

References 6 publications

Pullout Testing of Soil Nails in Gneissic Residual Soil

Pullout Testing of Soil Nails in Gneissic Residual Soil

3D Roughness Measurement of Failure Surface in CFA Pile Samples Using Three-Dimensional Laser Scanning

Distributed Fiber Optic Sensing of Axially Loaded Bored Piles

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