Supports, excavation

Excavate trench and use bentonite slurry to support excavation... 

Suitable and sufficient equipment is provided to support excavations and is installed, altered and dismantled under the supervision of a competent person... 

Welsh JP (1992) Grouting techniques for excavation support. Excavation Support for the Urban Infrastructure. ASCE, New York, pp 240-261 Xanthakos PP, Abramson LW, Brace DA (1994) Ground control and improvement. Wiley, New York, p 910 Yasuda S, Ishihara K, Harada K, Shinkawa N (19%) Effect of soil improvement on ground subsidence due to liquefaction. Spec Issue Soils Found 99—107... 

The use of tie-backs to support excavations has not supplanted conventional bracing systems for wide excavations. There are many situations where tie-backs cannot be used, and their cost advantages are non-existent or only marginal in soils where long anchors are needed to develop the required pull-out resistance. 

A "pipe trench" is an installation of process and utility piping on supports within a below grade, open excavated trench. Pipe trenches may provide some protection from damage due to explosion overpressures or explosion fragments or missiles. 

Such facilities are deemed to include any dam or other structure serving to contain, retain, confine or otherwise support such a facility, and also to include, but not be limited to, heaps and ponds, but excluding excavation voids into which waste is replaced, after... 

For high, heavy tanks, a foundation ring may be needed. Prestressed concrete tanks are sufficiently heavy to require foundation rings. Foundations must extend below the frost line. Some tanks that are not flat-bottomed may also be supported by soil if it is suitably graded and drained. When soil does not have adequate bearing strength, it may be excavated and backfilled with a suitable soil, or piles capped with a concrete mat may be required. 

According to Robert T. Mueller of the State of New Jersey Department of Environmental Protection (NJDEP), demonstrations conducted by the vendor have supported the premise that the cost to vitrify waste into nonleachable materials is substantially lower than the excavation and relocation of these materials to regulated landfills as a means of permanent disposal (D17164M,... 

V, described elsewhere (4), represents our only example of an excavated ivory with a nitrogen content greater than 1%. The presence of free carbon seems to have protected partially the collagen from the action of groundwater and bacteria. This observation is supported by the gen-... 

The costs of cleaning up hazardous waste, petroleum, and other contamination can be significant. Superfund sites commonly cost more than 30 million to remediate. The State of New York estimates that it would cost approximately 15— 20 million to excavate and dispose of wastes at a small industrial landfill, or approximately 3 million for the lower-cost alternative of capping [New York Department of Environmental Conservation (NYDEC) 2007]. Although costs are highly variable, it is clear that environmental cleanup is very expensive, and that like site assessments, cleanup will not happen without significant financial support. 

Historical documents do, however, record dates for the construction of the Metropolitan Cathedral, the floor of which was laid in 1573, sealing underneath deposits of the first 50 years of colonial occupation and the earlier Pre-Colombian period. During the installation of support pylons at the cathedral in 1975 and 1976, 182 pits were sunk through the floor, allowing excavation and sampling of the early colonial deposits. Majolica ceramics from these excavations assigned to non-Spanish types are assumed to be from a Mexico City production. Despite the lack of more detailed information, the claim is made (2) that, as Mexico City was the most important city of New Spain for the entire 16th century, the earliest demands of the market for better dishes must have been met by local craftsmen. 

We are grateful to Avraham Biran from the Hebrew Union College in Jerusalem who, as director of excavations at Tel Dan, granted permission to remove and analyze these materials. We also thank Moshe Dothan of Haifa University, Director of Excavations at Tel Akko for permission to remove and analyze materials. This work was supported, in part, by a Reactor Sharing grant provided by the U.S. Department of Energy to UCI. 

We have been able to distinguish two distinctive groups of pottery among the majolica sherds excavated from Spanish sites in the New World. These distinctions are based on the examination and analysis of the paste portions of the sherds and have involved the combined use of neutron activation analysis, x-ray diflFraction analysis, and petrographic examination. Preliminary investigations of the relationships of each of these two groups of sherds to sherds of known origin have also been undertaken. There is evidence to support a Spanish source for the sherds from sites in the Dominican Republic and Venezuela and a Mexican source for the sherds excavated in Mexico City. 

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