(i) Cementing the future, Berti, D.J.; Koutsoftas, D.C.; Lindquist, E.S., Civil Engineering, Vol. 68, No. 12, 1998 ASCE, pp. 46-48.
     The reconstruction of the Cypress Freeway in Oakland, Calif., required some of the most extensive and innovative uses of soil-cement mixing in the U.S. The following problems are discussed in the paper: dewatering, soil-cement solutions, soil-cement piles, BART underpinning and a novel solution. The success of the Cypress Contract B project shows the versatility of in situ soil-cement mixing for diverse temporary and permanent construction applications. Future advances, such as the development of jet-grouting techniques for constructing even larger columns, will probably reduce costs even further and expand the uses of soil mixing in difficult geotechnical applications.

Key words: Soil-cement, Jet grouting, Dewatering

(ii) Geotechnical challenges faced on Line 2 of the Greater Cairo Metro System, Campo, D. W. and Richards, D. P., Proceedings of the Geo-Congress, Big Digs Around the World, GSP No. 86, ASCE, 1998, pp. 358-379.
     This paper describes the geotechnical challenges faced during the design and construction of Line 2 of the Greater Cairo Metro System. The line is 19 km long, 13 km was constructed underground within the waterbearing Nile valley alluvium. The underground works included construction of cut-and-cover tunnels and stations using diaphragm walls, top-down methods, and state-of-the-art computerized injection grouting. General aspects of the bored tunneling are discussed, along with an innovative new method successful in minimizing surface settlements. Finally, construction of special hand-mined connections to the bored tunnels, TBM entry and exits methods from underground stations, and a major building underpinning effort is discussed.

Key words: Subways Construction, Tunneling

(iii) Jet grout stabilized excavation beneath an existing building, Ho, C. E. , Proceedings, Geotechnical Special Publication No.80, 1998, ASCE pp. 1-15.
     A new single basement was constructed as part of a building refurbishment project in Singapore. The excavation was carried out within the tight confines of the existing building. The sides and bottom of the excavation were stabilized by jet grout columns installed using the triple-tube technique. The excavation was carried out without shoring. The installation of the jet grouting works and subsequent excavation was monitored by geotechnical instruments. This paper presents the monitoring data obtained and discusses the influence of the jet grouting and construction activities on the surrounding ground and structures.

Key words: Jet grouting, Tunneling, Excavation

(iv) Behaviour of ground anchorages under cyclic loading, Merrifield, C.M. and Carey, J.M, Proceedings of the Institution of Civil Engineers, Geotechnical Engineering, Vol. 131, No. 3 1998, pp. 133-140.
     In the design of grouted ground anchorages the greatest uncertainty in the prediction of anchorage behaviour resides in the interaction between the grouted fixed length and the surrounding soil or rock. While there are generally accepted international practices for in situ anchorage tests, both at time of installation and at some time during the working life of the anchorage, at no time is the anchorage subjected to a test which involves a large number of repeated or cyclic loads, even when the predicted working load pattern suggests that it is appropriate. This paper investigates the behaviour, under repeated loading, of stiff right cylindrical model anchors installed vertically in the ground. All tests undertaken on the geotechnical centrifuge ensured that the anchors were correctly subjected to field-scale stresses.

Key words: Anchors, Cyclic loading

(v) Compaction grouting to reduce seismic risk and collapse potential for freeway storm drain system, Reed, John W.; Hourihan, Daniel T.; Thornton, G. J. Proceedings, Geotechnical Earthquake Engineering and Soil Dynamics III, Vol. 1, 1998, pp. 666-677.
     The deep storm drain system for the Century freeway in Los Angeles began to show signs of significant distress within a few years of original construction. Several sinkholes and open depressions developed at on-ramps, off-ramps, overcrossings, slopes, and around a new pumping plant. Geotechnical analyses revealed erosion and piping of significant quantities of granular backfill soils into the deep storm drain system, primarily at unsealed pipe joints. The result was collapsible voids around and above the storm drains, low-density bedding and backfill soils subject to differential settlement, and seismic risk due to liquefiable fine sands below a very shallow groundwater table. Compaction grouting was used to help restore the overall integrity and stability of 5.1 kilometers (3.2 miles) of the storm drain system by reducing liquefaction and settlement potential of coarse-grained and fine-grained foundation soils, respectively, as well as filling any macroscopic subsurface voids that might exist. Cone Penetration Testing (CPT) established the condition of soils around the storm drains prior to compaction grouting. A true low-mobility grout mixture was then injected to fill voids and improve soil properties from a depth of 1.5 m (5 ft) below the freeway, to a depth of 1.5 m (5 ft) below the bottom of the storm drain. Post-grouting CPT data established that the design performance criteria for the compaction grouting program had been achieved, including a marked decrease in the liquefaction potential of sandy soils in areas of groundwater table as shallow as 1.5 m (5 ft).

Key words: Compaction grouting, Cone penetration tests