SANS 10120-3 DE-1984 Code of practice for use with standardized specifications for civil engineering construction and contract documents Part 3 Guidance for design Section DE Small.pdf

1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA

2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any

3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. SABS 0120 : Part 3 section DE-1984 Small earth dams clause PART 3 : GUIDANCE FOR DESIGN SECTION DE CONTENTS PRE-TENDER CONSIDERATIONS . Investigations De

4、signated sources of material for embankment . Impact of relat.ively high cost of preliminary investigations Trial embankment Dispersive soils/clays Administration Tenders Documentation . Clearing the site of structtlres . “All-in“ clearing . Clearing dam basin Project specification . Testing for qua

5、lity control . Desicrnatinq sources of embankment materials . . Scheduling . Labour-based projects DESIGN REQUIREMENTS . Dispersive Soils/Clays References . Example of the use of dispersive soils . . Gravel Capping Drains . APPLICABILITY OF OTHER CODES . TEST PROCEDURES . General OlJALITY CONTROL AN

6、D OTHER CONSIDERATIONS General . Design Fai.lures and Disputes Disputes over classification of materials . . Design failures Page Number March 1984 Approved by the COUNCIL OF THE SOUTH AFRICAN BUREAU OF STANDARDS ISBN 0-626-06885-1 SABS 0120 : Part 3 Section DE-1984 Small earth dams SABS 1200 DE : S

7、MALL EARTH DAMS NOTE: The clause number(s) given at the beginning or after the heading of a clause is/are, unless otherwise stated, the number(s) of the relevant clause(s) of SABS 1200 DE. 1. PRE-TENDER CONSIDERATIONS 1.1 INVESTIGATIONS 1.1.1 Designated Sources of Material for Embankment. Some preli

8、minary investigation into sources of material for the embankment is essential to determine whether a stable structure can be built at a reasonable cost. (See also 1.3.6 below.) 1.1.2 Impact of Relatively High Cost of Preliminary Investigations. Because of the high cost of preliminary investigations

9、and the fact that the main expenditure is usually reserved for the dam site itself, it is not always pssible to he certain how much material can be won from each borrow area at small dam sites. If the distances from the dam site to two or more borrow areas differ to any extent, the haulage costs fro

10、m each borrow area will affect the cost of the embankment appreciably (see 1.3.6 and 1.3.7 below). 1.1.3 Trial Embankment (Subclauses 7.4 and 8.3.7). Adequate pre-tender testing of the materials available within a reasonable distance of the dam site will generally be cheaper for the employer than th

11、e construction of a trial embankment at the same rates as for the construction of the main embankment. Unless it is stated in the tender documents that a trial embankment will NOT be ordered, the rates tendered will inevitably be inflated to cover the extra costs of handling small quantities for a t

12、rial embankment. If there is any doubt, preferably schedule the trial embankment separately as a set of provisional items. 1.1.4 Dispersive Soils/Clays. Check the proposed embankment foundation and materials for dispersive soils/clays. If dispersive soils/clays are proved to be present and no other

13、suitable material is available in sufficient quantities, take special precautions with the design of the embankment, and in the project. specification specify special construction measures. (See also 2.1 below.) 1.2 ADMINISTRATION 1.2.1 Tenders. Before a tender is awarded, ensure that all queries in

14、 regard to the acceptable tender have been dealt with and that agreement has been reached in writing on the rates for variations from the original schedule. 1.3.1 Clearing the Site of Structures (Subclauses 2.1 and 5.2.1.l(h). Consider whether requirements for the clearing of structures should be co

15、vered by means of a project specification clause. 1.3.2 “All-in Clearing (Subclause 5.2.11. Where a single rate or sum applies to the clearing of trees of all sizes, i.e. “all-in“ clearing, see Subclauses 1.1.2, 1.3.3, and 1.3.6 of Section C. 1.3.3 Clearing Dam Basin (Subclause 5.2.1.4). Where the c

16、ontract requires the dam basin to be cleared, ensure that the drawings indicate clearly the limits of such clearing. 1.3.4 Project SpeciEication. Ensure that action has been taken on Sections AD and UE of Part 2 of the code and on 1.1.4 above, as applicable. 1.3.5 Testing for Quality Control (Subcla

17、uses 5.2.3.2 and 8.1.3). Testingby the contractor to control the quality of his own work forms part of his responsibility. Checking by the engineer should normally be carried out only after the contractor has stated that his work is in order. Under such circumstances the relevant provisions of Subcl

18、ause 8.1.3 of SABS 1200 DE will apply. Where this is not to be the case, ensure that the engineers requirements are set out fully, as the cost of testing may be considerable, particularly in remote areas. 1.3.6 Designating Sourcesof Embankment Materials. (Subclause 8.3.5). Where the source of each m

19、aterial for each part of the er b) “Dispersive soil Problem at Los Esteros Dam“, hy McDaniel, T.N. and Decker, R.S., published in the journal of the C;eotechnical Engineering Division, ASCE, Vol 105, No. GT9, 1979; C) “The Control of Water“, by Parker, P.A.M., published by G. outl ledge and Sons, Is

20、ondon 1913; d) “Piping in Earth Dams of Dispersive Clay“, by Sherard, J.L., Decker, R.S., and Ryker, N.L., published in Proceedings, Speciality Conference on the Performance of Earth and Earth Supported Structures, ASCE, Vol. l, 1972; e) “Identification and Nature of Dispersive Sojls“, by Sherard, J

21、.L., Dunnigan, L.P, and Deckr, R.S., published in the journal of the Geotechnical ngineering Divsion, ASCE, Vol. 102 No. GT4, 1976; f) “Pinhole Test for identifying Dispersive Soils“, by Sherard, S.L., lknnigan, LP., Decker, H.S., and Stelle, E.F., published in the journal of the eotechnical Enginee

22、ring Division, ASCF:, Vol. 102 GT1, 1976; and g) “Swumary - Evaluation of Sympasium on Dispersive Clays“, by Sherard. J.L. and Decker, R.S., published in ASTM STP 623, 1977. Example of the Usebf Dispersive Soils. For a description of the design and methods adopted with success on a sjte where only d

23、ispersive soils were available, see the paper “The identification and use of dispersive soils at Elandsjagt Dam, South Africa“ by Melvill, A.L. and Mackellar, D.C.R., published by AA Balkema of Rotterdam for the Seventh Regional Conference for Africa on Soil Mechanics and Foundation Engineering, ACC

24、RA, 1980. GRAVEL CAPPING. Ensure that the design includes provision of a gravel capping of sufficient tnickness to maintain the moisture level of the top of the core. Ensure also that the instructions to the party responsible for maintaining the finished small earth dam include a requirement that th

25、e gravel capping be properly maintained (see 5.2.2 below). DRAINS. Ensure that the design incorporates adequate drains. APPLICABILITY OF OTHER CODES There are no other SAFS codes of practice applicable to the design of small earth dams. TEST PROCEDURES GENERAL. Except where otherwise specified, the

26、test procedures recormended in TMH 1) are applicable. QUALITY CONTROL AND CYPHER CONSIDERATIONS GENERAL. Apply the relevant recommendations of SABS 0157 ta the design of small earth dams. DESIGN FAILIJRES AND DISPUTES Disputes over Classification of Materials. See Subclause 3.2 of Section DE of Part

27、 5 of the code. Design Fail-. Drying out and cracking of the clay core is a primary source of small earth dam failures. Such cracking frequently starts from the exposed top of the core, and can be prevented by maintaining the quality of the gravel capping. l) Standard methods of testing road construction materials, published by the NITHR. 2) Quality management systems.