Geoscience Reference
In-Depth Information
The first of these experimental programs has been described in detail by Yoshisaki, et al.
(2001),andonlythesalientfeaturesarepresentedhere.Theexperimentswereperformed
to evaluate the performance of steel gas distribution pipelines with 90
◦
elbows. The
response of pipeline elbows, deformed by adjacent ground rupture and subject to the
constrainingeffectsofsurroundingsoil,isacomplexinteractionproblem.Acomprehen-
sive and reliable solution to this problem requires laboratory experiments to characterize
the 3-D response of the elbow under axial and flexural loading, an analytical model that
embodies soil-structure interaction combined with 3-D elbow response, and full-scale
experimental calibration and validation of theanalytical model.
Figure 17.9 illustrates the concept of the large-scale experiments. A steel pipeline with
an elbow was installed under the actual soil, fabrication, and compaction procedures
encountered in practice, and then subjected to lateral soil displacement (Yoshisaki et al.,
2001).Thescaleoftheexperimentalfacilitywaschosensothatlargesoilmovementsare
generated, inducing soil-pipeline interaction unaffected by the boundaries of the test
facility.Figure17.10showstherupturedexperimentalpipelineintwohalvesoftheexper-
imental basins that held a total of 60-65 metric tons of sand. The basins were displaced
1m relative to each other, as shown in the figure, to simulate the type of abrupt displace-
ment generated by liquefaction-induced lateral spread, landslides, and surface faulting.
The sand was obtained from a glacio-fluvial deposit, containing approximately 2% by
weight of fines (see Figure 17.13). It was placed and compacted in 150-mm lifts with
strictcontrolsonwatercontentandinsitudensity.Experimentswereperformedwithdry
Fig. 17.9. Experimental concept for ground rupture-pipeline experiments
2
m
1 m of Lateral
Movement
Pipeline Rupture
Fig. 17.10. Overhead view of soildeformation effects on experimental pipeline
