Engineering Geology Office Manual
Total Page:16
File Type:pdf, Size:1020Kb
ENGINEERING GEOLOGY .Collection of data; operation of the feature and also the issues' impact .Collation, analysis, and interpretation of data; on the cost of the design, construction, and operation and and maintenance. Critical issuesshould be emphasized .Preparation of findings. to make certain they are thoroughly scrutinized and evaluated. ENGINEERING GEOLOG,y EVALUATIONS Throughout the entire process of arriving at a deci- The impact of the geologic considerations and their sion or conclusion, the engineering geologist must ex- specific issuesupon the propo~ied engineering works ercise sound judgment. A discussion of each issue and must be evaluated throughout the engineering geol- its evaluation, including the data required to reach ogy program. Conclusions, decisions, and recommen- the conclusion should be documented in the "Geo- dations to address these issues must be provided technical Considerations" portions of any geologic re- during interim data submittals and in the final engi- port. The amount of detail of the discussion of ally neering geology report. To accomplish this, those rel- issue generally will depend upon its criticality and the evant geologic issueswhich must be addressed during type of the engineering geology report under prep- the engineering geology progr:im must be identified. aration. Individual discussion of each issue will ensure A convenient way to approach the identification and that relevant issues have been identified and ad- selection of issuesis to consider :separatelythe geologic dressed, are subsequently given proper consideration considerations groups on a site'-by-siteand structure- for design concepts and constructability, and are ap- by-structure basis. This should be done by: (I) refer- propriately monitored during construction and ring to the checklist of common issues in chapter 6; (2) discussing the program with involved parties; (3) operation. seeking the assistanceof experienced engineering ge- ologists and other professionals; and (4) reviewing and BIBLIOGRAPHY studying similar case histories. [ 1] Glossaryof Geology,American Geological Institute The issues should be categorized as to their relative third edition, American Geological Institute, Falls importance for a safe and economical design, proper Church, VA., 1987, page 788. 4 ENGINEERINGGEOLOGY 3. Document the investigatjion program on the following programs require much thought and dis- ACER Field Exploration JR.equestform; cussion. A phasedprogram is usually the most efficient and economical. The rationale for any exploration 4. Prepare transmittal memorandums; should be documented so that all understand the use and value of the data. The TDP requires a Technical 5. Inform other representatiives of field inquiries Memorandum (formerly the Engineering Geology Re- and of any actions taken. .'This may require dis- view Memorandum) to document these data and cussion and decisions by the group; known conditions. Additional exploration should be dependent on the results of the earlier explorations 6. Monitor the exploration program; and any corresponding changes in design concepts. It is very important that the field geologist have full in- 7. Prepare memorandums Dlodifying original in- put into any stage of the exploration program and vestigation program; and that he or she concur by initialling (or authorizing their initials) on the fInal program, as concurring, on 8. Assure that data reports are distributed. Bureau of Reclamation Form 7-2145, "ACER Field Exploration Request." It should be emphasized that Other members of the team are responsible for no- the team geologists' responsibilities do not end after tifying the coordinator of any inquiries, discussions, formulation of the initial exploration program. problems, or information received from field Most schedules are based on political decisions and personnel. are certainly budget oriented. Therefore, our data The initial meeting of the Exploration Team should collection mayor may not be allowed adequate time be held at the feature site. It is highly desirable that for the amount of data specifically required. The Ex- the team meet at the site with field geologists and ploration Team must make a reasonable evaluation of materials specialists who will be performing the in- time required to collect these data and make the nec- vestigations before the 'program is formulated. It is essary adjustments that will accommodate both the very important that the investigation program be sys- project and the Denver Office. Team members must tematically thought out and rationalized. For this rea- realize that .commitments should be met, and they son "on-the-spot" or hastily derived investigations should not make a commitment that can't be met. programs should be avoided. Prior to this meeting, If scheduling problems arise, they should be referred the field geologist should have become very familiar to the PMT. This team has the authority to address with the site geology and antici,pated geologic design schedule changes or reduce the program. They also and construction consideration:s. Much of the initial realize that when a program is reduced, the degree exploration program will be based on the field geol- of risk increases. ogist's knowledge of local geologic conditions. It can be of great value if the field geologist prepares a pre- Other important duties of the field geologist, as a liminary or recommended explolration program based member of the Exploration Team, include the sub- on his knowledge of the area. It is recommended that mittal of interim data, interpretation of data, com- the preliminary program be distributed to Explora- municating schedule or program problems and tion Team members prior to the site visit. The pro- completion, recommending modifications to the ex- gram should attempt to answc~rboth geologic and ploration program, and preparation of the Geologic geotechnical concerns. Although the program may Design Data Report. The Geologic Design Data Re- not be used in its entirety, it doe~ioffer a starting point. port serves to document the data collection and re- By the time the program is finalized, the Exploration suits. These data can be adjusted and supplemented Team should be able to justify fully all aspectsof the as needed. Just how these data are to be formulated program. Additional coordinat:ion meetings will be and used should be clearly defined prior to issuance held as necessaryduring progr.~ssof the program to of the ACER Field Exploration Request. resolve problems and make required modifications. INTERPRETIVE GEOLOGIC DATA AND The goal of the exploratory or investigation program PRESENTATION IN REPORTS AND is to prioritize and produce the amount of data re- SPECIFICATIONS quired for that level of study or design. These data are to be obtained in the most efficient manner and In an effort to improve the overall quality of Bureau at an economical cost. The team then transforms these of Reclamation specifications and reduce construction data into a report or the specifications in the most changesand claims, the Total Design Processcalls for efficient manner possible. the inclusion of geologic information that conveys both the known and anticipated geologic conditions. No attempt should be made to formulate an all-inclu- To accomplish this, accurate and timely data and inter- sive fiml program while in the field. The initial and pretations of these data must be presented. Design 6 ENGINEERING GEOLOGY Table 3-1. -Geologic Milestones and Responsibility. I I I NO WORK I None 1 1 Sched 1 None START TM (Technical Memorandum) ! Exploration Team Members. I I ACER Field Exploration Request(s) : Principal Geologist with team I : approval. Concept : Prelimiinary Ongoing Submittals : Field Geologist. ! Geolog~c Design Data Report(s) : Field Geologist with approval i by Principal Geologist. i Geologic Design Data Review ! Principal Geologist. : Memorandum(s) : Engineering Geology Considerations for : Principal Geologist. I ! Conceptual Design TM I I I CONCEPTC I : Final {;eologic Design Data Report Field Geologist. Design ! Geologic Design Data Review Principal Geologist. : Memorandum : Draft Engineering Geology Considerations Principal Geologist. : for Design and Construction TM I DESIGNC I I ! Supple'ments to Geologic Design Data ! Field Geologist. Draft : Report Spec : Specifications Paragraphs and Drawings i Principal Geologist. : Final Jt:ngineering Geology Considerations : Principal Geologist. I ! for Design and Construction TM SPECD I I Review ! ! Revie\'1' spec paragraphs and drawings Principal and Field Geologists. REVIEWC I I I I : Principal Geologist. Review of Specifications I Revise Specifications Drawings and Paragraphs I Geology Division/Branch Signed through Approved (anytime ! Chief. from SPECD to SPECB) SPECB Book : Geologic Requirements During ! Principal Geologist. : Construction Memorandum pre (at least: two months prior to AWARDC) I I BOOKC I 8 ENGINEERING GEOLOGY Table 3-2. -Required Action by Geologic Staff. Flags and Action required by Geology stages I I NO WORK ! None officially. However, if geologic map of feature is not available, field geologist could start : mapping if approximate alignment or location is shown. Also, compile, review, and : summarize available data. I Field geologist provides scheduling information to Project Management Team. Site mapping, Sched data revielfi. START I i Site mapping and preliminary interpretations. Field geologist proposes explorations. : Design and Exploration Teams formed. : Site visit(s).