Centrifuge modelling of the effects of soil loading on flexible sewer liners

Abstract

This paper presents an experimental study of the effects of soil loading on large-diameter, close-fitting, non-bonded, flexible sewer liners as typified by ‘cured-in-place pipes’ (CIPP). CIPP is the process whereby a polymeric pipe lining is cast directly against the wall of a deteriorating sewer pipe. The transfer of soil loading to CIPP liners is strongly influenced by the interaction between the existing host pipe and the surrounding soil. In adjusting to deterioration events of the host pipe and possible void formation in the soil, the existing pipe-soil structure deforms and interacts with the liner inside it. By monitoring deformations of the liner and host structure the magnitude of load transfer can be inferred. The paper describes 1/30th scale physical models tested in dry sand under 30g of centrifugal acceleration. The models included: (a) a host pipe with two simulated modes of deterioration; (b) an instrumented close-fitting, non-bonded, flexible liner; (c) voids in the soil; and (d) moving, heavy traffic loading. The tests showed that, even under extreme loading conditions, the deformations of the liner are relatively small (2–3% of diameter), implying that the presence of a thin, flexible non-bonded and close-fitting liner has an important stiffening effect on the response of the deteriorating host pipe. The important influence of void position in the surrounding soil was also demonstrated.

Contributions to Géotechnique 1948–2008: Physical modelling

“…These include the simple approach of draining heavy fluid to simulate the reduction in stress during excavation or tunnelling (Davis et al, 1980;Bolton & Powrie, 1988), which has been augmented by techniques for in-flight 'concreting' of diaphragm walls (Powrie & Kantartzi, 1996), insertion of props (Richards & Powrie, 1998, Fig. 2(a)), loading of adjacent piles (Choy et al, 2007), and deterioration of sewer linings (Spasojevic et al, 2007).…”

Science Mapping for Recent Research Regarding Urban Underground Infrastructure

“…Cluster 7 is plotted in the lower-right corner of Figure 9, which is relatively the "loneliest" cluster compared with other clusters in the figure. This cluster mainly covers the research in the structure analysis domain indicated by the keywords of soil-structure interaction [81][82][83][84][85] and finite element method [86][87][88].…”

Damage evaluation of a PCCP joint with a localized soil void and broken wires

“…Considering that the final effect of soil voids is the release of support from the pipe, the geometrical shape is the second most important factor. For convenience, the void has been idealized as a simple circular shape in previous papers (Gao et al, 2014;Meguid and Dang, 2009;Moore, 2008;Spasojevic et al, 2007).Based on the calculation results of the void effect and trial calculation (Li and Feng, 2020), the void size was selected with the dimensions of a 10 cm depth, 0.8 m width, and 1.25 m longitudinal length (1/4 of the single pipe length), as illustrated in Figure 2. In this paper, the soil void evenly located under the bell-and-spigot joint was simulated by ''birth-and-death technology'' in the finite element method.…”