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Introduction
Published in Raymond Cheung, Ken Ho, Soil Nailing, 2021
Soil nailing is also a suitable scheme for strengthening retaining walls and embankments. The technique has been widely used in stabilizing existing retaining walls and embankments as part of roadway or railway projects (e.g. Perry et al., 2001; Phear et al., 2005; Lazarte et al., 2015). It can be applied to various types of retaining walls such as stone, brick, and concrete. Soil nails can be installed directly through the wall face if it is sufficiently stable to resist drilling. However, due consideration should be given to the connection details between soil nail heads and the wall, particularly where the wall is suffering from severe distress. As further ground movement is necessary to mobilize tensile force in soil nails, special measures (such as grouting) may be required to stabilize the ground immediately behind the retaining wall.
Tests on a flat arch concrete block retaining wall
Published in Jan Kubica, Arkadiusz Kwiecień, Łukasz Bednarz, Brick and Block Masonry - From Historical to Sustainable Masonry, 2020
M.C. Kurukulasuriya, N.G. Shrive
Arches have been used in structures for more than 4000 years and many ancient, medieval and modern arches still exist with inherent structural integrity. Although arches have been used in numerous types of structures such as bridges, aqueducts, dams, roofs and wall openings, utilizing an arch shape in a retaining wall is not common. Similar to an arch dam, an arch retaining wall will resist the lateral pressure of soil through arch action, avoiding “snap-through” of the wall and minimizing tensile stresses. Retaining walls are typically constructed using concrete, steel or timber. However, in this instance it is desirable to use concrete blocks as the building material due to ease of construction, cost effectiveness and aesthetic appearance. The shape of the arch is more convenient to be constructed with blockwork as the need for formwork is alleviated. Furthermore, the arch shape provides the wall with ample robustness so that reinforcement is not required. This makes such a wall ideal for low-rise retaining walls in cities, opening a new market in which masonry can compete.
Lateral earth pressure and retaining structures
Published in An-Bin Huang, Hai-Sui Yu, Foundation Engineering Analysis and Design, 2017
Water has no strength ( Ø′=0), its Ko = Ka = Kp = 1. Because of this, when calculating the lateral earth pressure below a water table it is necessary to separate water pressure from that of the soil. As demonstrated in Example 5.1, when water is present, the total lateral pressure can be significantly higher than soil pressure that is calculated using the effective stress. In addition, water can freeze and expand in cold regions, and that further increases the loading on the retaining wall. Thus in practice we normally would install a drainage system at the base of the retaining wall to make sure that no water can accumulate behind the retaining wall. Details for the design of the drainage system are described in the following sections.
Calibration of resistance factors for gravity retaining walls
Published in Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 2023
Pengpeng He, Gordon A. Fenton, D. V. Griffiths
The design of retaining walls generally should satisfy two types of requirements, that is, internal stability for structural safety of retaining walls associated with wall material properties, and external stability for geotechnical safety related to soil properties. Traditional geotechnical design of external stability for retaining walls was based on deterministic methods employing factors of safety. To harmonise with structural design of internal stability, geotechnical design has been migrating from the traditional allowable stress design (ASD) towards the load and resistance factor design (LRFD) approach. Examples of modern LRFD in geotechnical engineering can be found in the Canadian Foundation Engineering Manual (CFEM) (Canadian Geotechnical Society 2006), and the Canadian Highway Bridge Design Code (CHBDC) (CSA 2019). The LRFD approach employs a geotechnical resistance factor, typically less than 1, to scale the geotechnical resistance to values having a sufficiently small exceedance probability. The design goal is to achieve the target safety level, or, equivalently, to achieve a target maximum acceptable failure probability, which, in turn, depends on the consequences of failure (e.g. potential losses, personal and societal safety requirements).
Role of Geogrid reinforcement and its diverse applications in the geotechnical engineering and allied fields: a-state-of-the-art review
Published in Australian Journal of Civil Engineering, 2023
Kiran Prakash K, Deendayal Rathod, Kasinathan Muthukkumaran
Fishman et al. (1993) conducted an experimental study on a full-scale concrete facing a mechanically stabilised tensor geogrid reinforced earth retaining wall that was used as part of a highway widening project. Internal and external stability must be considered when designing a retaining wall. Exterior walls ensured the external stability of the system. The external instability issues observed were sliding failure, overturning failure, tilting/bearing failure, and slip failure. However, the author only looked at the internal stresses and strains within the system. The internal failure modes in the design of reinforced soil retaining walls were tension failure and pull-out failure. The study revealed that the tensile strength and stiffness of the reinforcing member should be adequate to prevent the breakage of the tensile member. Moreover, pull-out failure could be eliminated by providing a sufficient length of the reinforcing members beyond the potential failure wedge. The observed vertical pressure induced near the wall facing was a smaller value than that at the centre and the other end of the retaining wall. This was due to the soil-arching effect observed near the wall face and the temperature stresses generated. This effect could be minimised by using a flexible articulated panel instead of a rigid concrete retaining wall.
Material Characteristics and Stability Analysis of Gravity Stone Walls
Published in Structural Engineering International, 2023
Turgay Cosgun, Cihan Öser, Savaş Erdem, Ali Koçak, Baris Sayin
Natural soils and filled soils consisting of different materials such as earth, sand and crushed stone can suffer shear failure due to lateral forces in the presence of a vertical plane between levels of different elevation. To prevent such undesired occurrences, low-angle terracing or sloping of retaining walls are preferred in the field. A retaining wall is defined as a structure that keeps changes in the soil surface to a near-vertical plane, and is used to prevent soil movement due to the natural angle of repose. The walls can be constructed according to four different designs, namely gravity, reinforced concrete, prestressed, and reinforced earth walls. Similarly, gravity stone walls are structures that are constructed using stones, rocks or concrete, with the intention being to counter the lateral pressure from the soil with its own gravity. These structures are designed to avoid the emergence of low tensile stress.1–3