Analysis of settlement of rock embankment with lattice frame reinforcement (LFR) system

Name: Rajakaruna Mohottige, Isuru Tharanga Dias

keyword: Coastal embankments

; Embankment settlement

; Field measurements

; Finite element analysis

; Lattice frame reinforcement (LFR)

; LFR mortar tube

Abstract: This study investigates the behavior of the Lattice Frame Reinforcement (LFR) system under rock embankments. The LFR system is used to reduce the rate of rock embankment settlement. The LFR system contains two main components, lattice framed injected mortar polyester tube (LFR mortar tube) and polyester underlying sheet (LFR sheet). Both components are knitted together before the injection of mortar into the tubes. After the mortar was properly set, an embankment was constructed on top of the LFR system. This method significantly reduces vertical pressure on soil under the embankment. It results in lower soil settlement due to less pressure occurring under the embankment. Two experimental embankments with the LFR system were constructed in Samut Sakhon province in Thailand for this study. The measured soil settlements under the embankments have been monitored for 30 months. Tensile tests were performed to understand the material's behavior of the LFR system. This study aims to explain the mechanism of the LFR system by applying Finite Element (FE) simulations and field measurements. The field measurement and analysis results showed that the LFR system could effectively reduce the long-term soil settlement caused by soil consolidation and self-weight of the embankment. FE Analysis shows that LFR mortar tubes behave mainly as tensile members and there is a significant effect of the grid spacing of the LFR mortar tubes on settlement reduction. Injected mortar in the LFR system provides construction stability and supports to keep the LFR tubes in a stretched condition. Mortar has a significant effect on the LFR system due to bond contact initiated during the injection of liquid mortar. Even though the mortar has started damage since the initial stage of the embankment construction, yet damaged mortar provides stiffness enhancement to the LFR tubes. This enhancement tends to increase the stiffness of the overall LFR system. A realistic contact between damaged mortar and LFR tubes is difficult to simulate. Therefore, this study presents a simple method to simulate the stiffness of the LFR mortar tube which considers stiffness of the LFR tube together with the contribution of stiffness of mortar in between cracks which are known as tension stiffening, in the analysis

Thammasat University. Thammasat University Library

Address: BANGKOK

Email: preserv@tu.ac.th

Name: Ganchai Tanapornraweekit

Role: advisor

Created: 2021

Modified: 2023-02-20

Issued: 2023-02-20

วิทยานิพนธ์/Thesis

application/pdf

DOI: 10.14457/TU.the.2021.79

eng

DegreeName: Master of Science

Level: Master's Degree

Descipline: Engineering and Technology

Grantor: Thammasat University

©copyrights Thammasat University

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