Roads and Bridges - Drogi i Mosty
14, 1, 2015, 5-17

Impact of repetitive loading on subgrade parameters derived from light weight deflectometer test

Bartłomiej Krawczyk Mail
Wrocław University of Technology, Faculty of Civil Engineering
Piotr Mackiewicz Mail
Wrocław University of Technology, Faculty of Civil Engineering
Published: 2015-04-22

Abstract

The most popular methods used for evaluation of subgrade bearing capacity with light weight deflectometer (LWD) assume linear-elastic behaviour of material. In these methods the input data used for identification of subgrade parameters are limited to initial loading cycles. Change of material parameters occurring under repetitive loading is not taken into consideration. Due to the characteristics of road building materials, including in particular granular materials, omitting the compaction resulting from repetitive loading is considered a rough approximation. Actually the subgrade parameters do change after each load application. It is generally accepted that after the third loading cycle (3rd drop) final degree of compaction is achieved and, as such, the vertical deflections obtained at the fourth, fifth and sixth cycles provide a representative measure of the subgrade parameters (calculated as an average of the three measurements). This paper presents the results of research carried out to verify the above-mentioned assumption by measuring subgrade displacements according to LWD test, followed by comparing the measurement results against numerically identified moduli of the respective layers. The authors have demonstrated that the identified subgrade parameters vary depending on the number of loading cycles (drops) in LWD test. Identification of subgrade parameters was carried out with 3D-FEM (Finite Element Method).

Keywords


Light Weight Deflectometer, repetitive loading, subgrade parameters change

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References


Badanie i ustalenie zależności korelacyjnych dla oceny stanu zagęszczenia i nośności gruntów niespoistych płytą dynamiczną. GDDKiA-IBDiM, Warszawa, 2005

Ruta P., Szydło A.: Drop-weight test based identification of elastic half-space model parameters. Journal of Sound and Vibration, 282, 2005, 411-427

TP BF-StB. Technische Prüfvorschrift für Boden und Fels im Straßenbau. Teil B 8.3. Dynamischer Plattendruckversuch mit Hilfe des Leichten Fallgewichtsgerätes, 1992

Gosk W.: Badanie podłoża gruntowego za pomocą płyty dynamicznej ZFG-01 – ocena zastosowania modelu sprężystego do interpretacji wyników. Aparatura badawcza i dydaktyczna, 15, 2, 2010, 99-106

Gosk W.: Zastosowanie metody stycznych do identyfikacji modułu sztywności podłoża gruntowego badanego płytą dynamiczną ZFG-01. Zeszyty Naukowe Politechniki Rzeszowskiej, Budownictwo i Inżynieria Środowiska, 59, 3/IV, 2012, 33-40

Sulewska M.J.: Doświadczenia ze stosowania lekkiego ugięciomierza dynamicznego. Drogownictwo, 58, 11, 2003, 365-367

Sulewska M.J.: Lekka płyta dynamiczna w zastosowaniu praktycznym. IBDiM, VII Międzynarodowa Konferencja „Trwałe i bezpieczne nawierzchnie drogowe”, Kielce, 2001, 139-145

ZTVE-StB 94: Zusätzliche Technische Vertragsbedingungen und Richtlinien für Erdarbeiten im Straßenbau, Fassung 1997, FGSV Verlag, Köln

ZTVA-StB 97: Zusätzliche Technische Vertragsbedingungen und Richtlinien für Aufgrabungen in Verkehrsflächen, FGSV Verlag, Köln

Oome A.J.J.A., Janssen J.L.G., Encica L., Lomonova E., Dams J.A.A.T.: Modeling of an electromagnetic geophone with passive magnetic spring. Sensors and Actuators A: Physical, 153, 2, 2009, 142-154

Light Weight Deflectometer for the dynamic plate load test. Terratest Instruction Manual. TERRATEST GbmH, Berlin, August, 2013

Bejarano M.O.: Subgrade Soil Evaluation for the Design of Airport Flexible Pavements. University of Illinois at Urbana-Champaign, 1999


Impact of repetitive loading on subgrade parameters derived from light weight deflectometer test

  
Krawczyk, Bartłomiej; Mackiewicz, Piotr. Impact of repetitive loading on subgrade parameters derived from light weight deflectometer test. Roads and Bridges - Drogi i Mosty, [S.l.], v. 14, n. 1, p. 5-17, apr. 2015. ISSN 2449-769X. Available at: <>. Date accessed: 19 Mar. 2024. doi:http://dx.doi.org/10.7409/rabdim.015.001.