Geologic Techniques in Civil Engineering 1143 



Stage D: Geologic Report 



The stage D geologic report should contain a comprehensive coverage 

 of all data on hand at the time of its preparation. In addition to data 

 acquired in stages A and B it should contain more of the detailed in- 

 formation obtained in stage C. The text should include (1) a brief 

 account of the regional geology; (2) a discussion of the kind of rock 

 and the effects of faulting, shearing, weathering, and like influences at 

 locations shown as such on the map, as well as other structural features, 

 such as dip, strike, jointing, and unconformity; relations of possible 

 leakage grouting programs; the amount of exploration necessary; and 

 data obtained in tests on undisturbed foundaiton materials as they have 

 been logged; (3) a description of cross sections; (4) a statement of 

 geologic conditions at sites of proposed appurtenant structures; (5) a 

 discussion of such matters as percolation tests and ground-water condi- 

 tions; (6) a description of materials for various construction purposes, 

 their origin, hauling distances, and quality, and the results of laboratory 

 testing; (7) and reference to special conditions affecting the pi-eliminary 

 design and estimate, such as landslides, vertical cliffs, the occurrence of 

 bentonitic materials, and similar matters. 



The following illustrations should be included: (1) a combined topo- 

 graphic and geologic map; (2) a sheet or sheets of geologic cross sec- 

 tions showing geologic interpretations as derived from all surface and 

 subsurface data available; (3) a map showing bedrock contours where 

 appropriate; (4) logs of drill holes, the test pit, and exploration tunnels; 

 (5) maps of prospective borrow areas showing locations of test pits and 

 cross sections, from which may be estimated the quantity and types of 

 material; (6) maps of profiles of sections showing the results of geo- 

 physical work; and (7) photographs, both ground and aerial. 



Stage E: Final Design and Specifications 



Upon the completion of stage D, exploration and investigations, the 

 designing engineer and geologist usually will undertake discussions 

 relative to the amount and type of exploration remaining to be done in 

 order to prove the competency of the geologic conditions at the specific 

 site of the more important structures appurtenant to the main feature. 

 Additional exploration will probably be determined and controlled by 

 the engineers rather than by the geologists. During this stage the geologists 

 should prepare and maintain up-to-date information, which can be sub- 

 mitted to the designer at periodic intervals, upon the completion of the 

 final design stage of exploration. An expansion of the geologic report 

 is usually necessary, and this will contain all of the information up to the 

 time of the preparation of the report. 



Construction 



During construction new information will be available as excavations 

 progress. This information should be recorded with appropriate changes 



