At the St Asaph Bypass, surface cracking developed along the crest of a modern highway cutting, above a cluster of badger setts excavated in the sandy soils of the cutting slope. This prompted concerns about the extent of the underlying tunnel systems and the possible existence of deep cavities lacking surface expression that might cause a potential slope instability problem. The full threat posed to the integrity of the cutting and to the safety of road users remained uncertain. In addition, intrusive investigations were deemed inappropriate and a non-invasive solution to the problem was required. Ground-penetrating radar was used along a 50 m stretch of the cutting to determine the full extent of the badger setts beneath the surface. The geophysical survey identified 324 m of tunnels and demonstrated that the tunnel network was generally shallow ( c. 0–2 m). Pronounced radar reflections characteristic of air voids were identified in the data and interpreted as the badgers’ access tunnels and living and nursery chambers whereas the more subdued features were interpreted as collapsed and abandoned diggings. This case history illustrates the benefits of using ground-penetrating radar to provide an understanding of slope stability and local ground conditions in areas of environmental sensitivity when non-intrusive investigations are required to provide reassurances in relation to public safety.

A high-resolution, ground-penetrating radar (GPR) investigation was performed on existing commercial shop premises within The Rows, Chester, UK to detect near-surface features, including a suspected Medieval undercroft (cellar), the location of which was unknown. GPR 2D profiles were acquired on a 0.5 m square grid-pattern both within the premises and on an exterior, Medieval raised walkway. Multi-frequency (250, 500 and 800 MHz dominant frequency) repeat-surveys were acquired in selected areas over the grid to resolve progressively deeper near-surface structures and used to generate 500 and 800 MHz horizontal 'time-slices'.Floor-supporting wooden beams with steel supports on the exterior walkway, the Medieval undercroft, associated passageways and a hitherto unexpected access trap-door were all successfully located. The undercroft was found to be air-filled. Three near-surface rectangular areas were identified and found not to be associated with the undercroft; these were interpreted to represent heterogeneous, rubble back-fill. Separate, isolated, raised areas were also identified ~1.5 m below present floor level; these were interpreted as relict brick column supports from a long-demolished, Roman building. GPR data acquired on the exterior raised walkway also found evidence for relict support structures from a former shopfront.All of the targeted anomalies were intrusively investigated and provided positive confirmation of the geophysical interpretations. Archaeological investigations of trial pits confirmed the site's varied history and depth to bedrock. GPR was therefore effective in this study to locate and characterize the modern, Medieval and Roman features without extensive intrusive investigation, whilst causing minimal disruption to commercial operations. These results demonstrate the effectiveness of carefully acquired and processed, high-resolution, closely-spaced GPR survey data in near-surface characterization for geotechnical investigations. GPR investigations to characterize Medieval and Roman foundations under existing shop premises: a case study from Chester, Cheshire, UKpied through Anglo-Saxon, Norman and Medieval times, to the present day. The Roman occupation left a lasting legacy: parts of the fortress walls and entrance gate sites were preserved and Medieval churches were built directly onto previous Roman building foundations (Lewis and Thacker 2003). In Medieval times, Chester was of strategic and economic importance, due to both the development of the port and its border position. During this time, construction was influenced by the major relict Roman fortress plan and structures; Lewis and Thacker (2003) suggested that 'The Rows' were created as a consequence of the location and availability of relict material in relation to Chester's varied topography. These unique structures are still present today, comprising a series of interconnected frontages, forming multi-level, raised walkways through commercial properties of various building dates and architectural styles (Fig. 2).

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LA STAZIONE STRADALE ROMANA DI ACQUAVIVA, ETRURIA MERIDIONALEAcquaviva era una piccola stazione stradale romana sulla via Flaminia a nord di Roma. Ricognizione intrapreso nel 1967–8 rivelò che in epoca repubblicana ed alto imperiale l'insediamento si addensava intorno ad un importante nodo stradale; nella parte bassa, a sud, fu identificato un altro complesso, con un notevole mausoleo alto imperiale che conteneva un'iscrizione. Nel periodo tardo-romano quest’area divenne il centro dell'insediamento principale, che può essere associato ad una diocesi di cui è nota l'esistenza nel periodo che va dal 465 al 502 d.C, ma non susseguentemente.

Ghirza is the site of a Roman frontier settlement in the pre-desert zone of Tripolitania in North Africa, 5 miles south-west of the confluence of the Wadi Ghirza and the Wadi Zemzem, 80 miles from the coast of the Gulf of Sidra and 150 miles (in a straight line) south-east of Tripoli. It is best known for its two groups of monumental tombs decorated with rough sculptured reliefs showing the life of the inhabitants; but it is also notable for other antiquities, and especially for its ‘town’ of fortified farmhouses, clustered together on the edge of the wadi.