Use of Synthetic, Fiber-Reinforced, Initial Shotcrete Lining at Devil's Slide Tunnel Project in California

Abstract

Fiber-reinforced shotcrete is widely used as a temporary excavation support in the construction of transportation tunnels and in other civil applications that are performed with the Sequential Excavation Method. Traditionally, steel fibers have been used in tunnel construction; however, the use of synthetic fibers is becoming more common. At the Devil's Slide Tunnel Project, on Highway CA-1 in Pacifica, California, a synthetic fiber mix was used to achieve the contract initial lining performance. The synthetic (polypropylene) fiber was used throughout the excavation phase of the twin highway tunnels and was tested with the round determinate panel test (ASTM C1550) for its capability to absorb energy after shotcrete section failure (flexural strength). The contract required the ASTM C1550 test to produce at least 320 J at 40 mm of deflection after 7 days. This paper discusses the testing program and summarizes its results. The overall performance of the fiber-reinforced shotcrete liner is discussed and evaluated on the basis of its reaction to deformation and its use in the tunnel.

Age-dependent changes in post-crack performance of fibre reinforced shotcrete linings

“…In each of these documents the minimum energy absorption requirement for FRS is related to the expected degree of ground movement. In Australian and North American practice (Bernard, 2013;Decker et al, 2012), energy absorption is specified on the basis of FRS performance using ASTM C1550 round panels (ASTM, 2012). ASTM C1550 panels have therefore been used to assess FRS performance throughout this investigation.…”

Development of Recycled Polypropylene Plastic Fibres to Reinforce Concrete

“…The specimen toughness is assessed in terms of the energy absorbed in loading the plate to some selected values of central deflection. This test has become popular for fibre reinforced shotcrete due to its high precision in post-cracking performance evaluation (Wang et al, 2004), and is often used in the mining industry (Decker et al, 2012). Its panel-based performance assessment is desirable because panels fail through a combination of stress actions that reflect an in situ behaviour of concrete footpaths more closely than other mechanical tests in the laboratory (Parmentier et al, 2008).…”

An Overview of the Research Trends on Fiber-Reinforced Shotcrete for Construction Applications

“…Due to their better energy absorption capability and post-crack strength, steel bers have been generally utilized in tunnel constructions [31]. On the other hand, the usage of polypropylene bers has grown in recent years because of their economic bene ts [32][33][34]. In comparison to polypropylene bers, steel bers with hooked-ends in the cementitious matrix enable better post-crack strength more effectively [35].…”