COE EC 1110-2-292-1998 COASTAL ENGINEERING MANUAL PART III《 第3部分》.pdf

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1、CECW-EH Circular NO. 1 1 10-2-292 COE EC 3330-2-292 3535789 0827245 OTO DEPARTMENT OF THE ARMY U.S. Army Corps of Engineers Washington, DC 203 14- 1 O00 EC 1 110-2-292 3 1 March 1998 EXPIRES 30 September 1999 Engineering and Design COASTAL ENGINEERING MANUAL, PART IiI Distribution Restriction Statem

2、ent Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-COE EC 3330-2-292 m 3515789 0827246 T37 m CECW-EH Circular NO. 1 1 10-2-292 DEPARTMENT OF THE ARMY U.S. Army Corps of Engineers Washington, DC

3、 2031 4-1 O00 EC 1 1 10-2-292 31 March 1998 EXPIRES 30 September 1999 Engineering and Design COASTAL ENGINEERING MANUAL, PART 111 1. Purpose. This circular transmits the draft copy of Part III of the Coastal Engineering Manual (EM 11 10-2-1 100) for your review, comment, and use. 2. Applicability. T

4、his circular is applicable to all HQUSACE elements and USACE Commands having civil works coastal responsibilities. 3. Discussion. About 10 existing coastal engineering manuals and the Shore Protection Manual are being combined into the Coastal Engineering Manual (CEM). The enclosed draft CEM, Part I

5、II (Appen- dix A) is the second section of the CEM to be completed. Reviewers should compare the draft CEM with EM 11 10-2-1502 “Coastal Littoral Transport,” EM 11 10-2-2302 “Construction with Large Stone,” EM 11 10-2-1004 “Coastal Project Monitoring,” and EM 1 110-2-18 10 “Coastal Geology to ensure

6、 that the useful portions of those manuals are covered in the CEM. Authors of the various chapters and their phone numbers are noted in the CEM outline (Appendix B). A summary discussion of the CEM, an out- line with the authors e-mail addresses, and an initial glossary of terms can be found on the

7、Coastal and Hydraulics Laboratory page of the Waterways Experiment Station Internet site at http:/bigfoot.cerc.wes.army.miik133.html. 4. Distribution Statement. Approved for public release, distribution is unlimited. 5. Action Required. The enclosed draft CEM, Part Iii should be reviewed for usefuln

8、ess, complete- ness, and interim guidance. Comments to be incorporated into the formal version of the CEM, Part LI1 should be directed to CECW-EH-D, ATTN: Mr. John P. Bianco, (202) 761-8501, FAX (202) 761-1485 or e-mail john.p.biancousace.anny.mil by 3 1 December 1998. FOR THE COMMANDER: ROBERT w. B

9、URKHARDT Colonel, Corps of Engineers Executive Director of Civil Works Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CECW-EH Circular NO . 1 1 10-2-292 COE EC 3330-2-292 3535789 0827247 973 9 DEPARTMENT OF THE ARMY U.S. Army Corps of Engineers Wash

10、ington. DC 20314-1000 EC 1 1 10-2-292 31 March 1998 Coastal Eng i neeri ng Manual Part 111 Chapter 1 COASTAL SEDIMENT PROPERTIES Table of Contents Page 111-1 .1 . Introduction . III-1-1 b . Sediment properties important for coastal engineering . III- 1-1 (2) Properties important in environmental que

11、stions . 111-1 -2 (3) Properties important in beach fills III-1-3 (4) Properties important in scour protection (5) Properties important in sediment transport studies a . Bases of sediment classification . III- 1-1 (1) Properties important in dredging . III-1-2 . III-1-3 . III-1-4 111.1.2 . Classific

12、ation of Sediment by Size . III-1-4 a . Particle diameter . III-1-4 b . Sediment size classifications 111-1 -5 c . Units ofsediment size . 111-1-9 d . Median and mean grain sizes . III- 1-9 e . Higher order moments III- 1-10 f. Uses ofdistributions . III-1-1 1 g . Sediment sampling procedures . III-

13、1-11 h . Laboratory procedures . III-1-14 111-1 .3 . Compositional Properties III-1-14 a.Mineruls III-1-14 b.Densi ty III-1-15 d.Strength . III-1-16 c . Specific weight and specific gravity . III-1-16 e . Grain shape and abrasion . III- 1-19 111.1.4 . Fall Velocity III-1-20 a . General equation III-

14、 1-20 b . EfSect of density . III-1-25 c . Effect of temperature . III-1-25 Coastal Sediment Properties 111-1 -i Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EC 11 10-2-292 31 Mar98 d . Eflect of particle shape . III- 1-25 e . Other factors . III-

15、 1-25 111.1.5 . Bulk Properties . III-1-26 b . Bulk density . 111-1 -29 c . Permeability . III-1-30 d . Angle of repose . 111-1 -30 e . Bulk properties of diferent sediments . 111-1 -30 (1) Clays. silts. and muds . 111-1 -30 (2) Organically bound sediment III-1-32 (3)Sandandgravel III-1-32 (4) Cobbl

16、es. boulders. and bedrock . III- 1-33 U . Porosity 111-1-26 111-1 .6 . References . III-1-33 111-1 -i Coastal Sediment Properties Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-COE EC 1110-2-292 rn 3515789 0827249 74b rn EC 1 11 0-2-292 31 Mar98 Lis

17、t of Figures Page Figure i-1-1. Example of sediment distribution using semilog paper; sample 21c - foreshore at Virginia Beach . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . III-1-6 Figure III-1 -2. Example of sediment distribution using log-normal paper . . .

18、. . . . . . . . . . . . . . . . III- 1-7 Figure III-1-3. Suggested composite sediment sample groups on a typical profile - example fi-om CHL Field Research Facility, Duck, NC . . . . . . . . . . . . . . . . . . . . . . . . . . . III-1-12 Figure III-1-4. Unconfined ultimate strength of three rock typ

19、es (Hardin 1966) . . . . . . . . . . . . . III-1-17 Figure III-1-5. Drag coefficient as a function of Reynolds Number (Vanoni 1975) . . . . . . . . . . . III-1-22 Figure i-1-6. Fall velocity of quartz spheres in air and water (Vanoni 1975) . . . . . . . . . . . . . . 111-1-24 Coastal Sediment Proper

20、ties 111-1 -i Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- COE EC 3310-2-292 m 3535789 0827250 4b8 m EC 11 10-2-292 31 Mar 98 List of Tables Page Table III-1-1 Relations Among Three Classifications for Two Types of Sediment UI- 1-1 Table 111-1 -2

21、 Sediment Particle Sizes . UI-1-8 Table III-1-3 Qualitative Sediment Distribution Ranges for Standard Deviation, Skewness, and Kurtosis . 111-1-1 1 Table III-1-4 Densities of Common Coastal Sediments 111-1 -1 6 Table III- 1-5 Average Densities of Rocks Commonly Encountered in Coastal Engineering 111

22、-1 -1 6 Table III-1-6 Soil Densities Useful for Coastal Engineering Computations . III-1 -29 111-1 -iv Coastal Sediment Properties Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-COE EC 3330-2-292 m 3535789 0827253 3T4 m EC 11 10-2-292 31 Mar 98 Chap

23、ter 111-1 Coastal Sediment Properties 111-1 -1. Introduction a. Bases of sediment classifcation. (1) Several properties of sediments are important in coastal engineering. Most of these properties can be placed into one of three groups: the size of the particles making up the sediment, the compositio

24、n of the sediment, or bulk characteristics of the sediment mass. (2) In some cases (in clay, for example) there are strong correlations among the three classification groups. A clay particle is, in the compositional sense, a mineral whose molecules are arranged in sheets that feature orderly arrays

25、of silicon, oxygen, aluminum, and other elements (Lambe and Whitman 1969). Clay particles are smail and platey. They are small in part because they originate from the chemical modification and disintegration of relatively small pre-existing mineral grains and because the sheet-like minerals are not

26、strong enough to persist in large pieces. The geologists size classification defines a particle as clay if it is less than 0.0039 mm. Because a clay particle is so small, it has a large surface area compared to its volume. This surface area is chemically active and, especially when wet, the aggregat

27、e of clay surfaces produces the cohesive, plastic, and slippery characteristics of its bulk form. Thus, the three classifications each identify the same material when describing “clay.” (3) On the other hand, most grains of beach sand are quartz, a simpler and chemically more inert material than cla

28、y minerals. in the geologists size classification, sand grains are at least 16 times larger and may be more than 500 times larger in diameter than the largest clay particle (4,000 to more than 100 million times larger in volume). At this size, the force of gravity acting on individual sand grains dw

29、arfs the surface forces exerted by those sand grains, so the surface properties of sand are far less important than surface properties of clay particles. Because sand grains do not stick together, a handful of pure dry sand cannot be picked up in one piece like a chunk of clay. Several differences b

30、etween clay and sand are summarized on Table iiI-1-1. More inclusive discussions of sediment sizes, compositions, and bulk properties are given later in this chapter. Table 111-1-1 Relations Among Three Classitications for Two Types of Sediment Bases of Classification Name of Sedlment Usual Composit

31、ion Size Range, Wentworth Bulk Properties Clay Clay Minerals Less than 0.0039 mm Cohesive (sheets of silicates) Plastic under stress Slippery Impermeable Sand Quartz Between 0.0625 mm and N oncohesive (SiO,) 2.00 mm Rigid under stress Gritty Permeable 6. Sediment properties important for comtul engi

32、neering. Sediment properties of material existing at the project site, or that might be imported to the site, have important implications for the coastal engineering project. The following sections briefly discuss several examples of ways that sediment properties affect coastal engineering projects

33、and illustrate their importance. Coastal Sediment Properties 111-1-1 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-COE EC 1110-2-292 3535789 0827252 230 EC 1 11 0-2-292 31 Mar 98 (1) Properties important in dredging. (a) A hydraulic dredge needs to

34、 entrain sediment from the bottom and pump it through a pipe. The entrainment and the pumping are both affected by the properties of the sediment to be dredged. The subject is briefly treated in the following paragraphs, but more details on dredging practice can be obtained from books by Turner (198

35、4) and Huston (1970). Other information is available through the Dredging Research Program of the U.S. Army Corps of Engineers. (b) Sediment can be classified for entrainment by a hydraulic dredge as fluid, loose, fm, or hard. Fluid muds and loose silt or sand can be entrained relatively easily by d

36、ragheads. Firm sand, stiff clay, and organically bound sediment may require a cutterhead dredge to loosen the sediment. Usually, hard material such as rock or coral is not suitable for hydraulic dredging unless the material has previously been well broken. (c) Sediment can be classified for pumping

37、by a hydraulic dredge as cohesive, noncohesive, or mitigated (Turner 1984). Cohesive sediments get transported through the pipe as lumps and nodules whereas noncohesive sediments disperse as a slurry, which is more easily pumped through the pipe. Mitigated sediments consist mainly of noncohesive sed

38、iments with a small amount of clay, which increases the transport efficiency of the pipe. (d) The diameter of the pipe and the size of the pump limit the size of the material which can be pumped. Usually, oversize material is prevented from entering the pipeline of a suction dredge by a grid placed

39、across the draghead, or the cutterhead reduces material entering the pipeline to adequate size. (e) Another property of the sediment important in dredging is the degree of its cohesiveness that allows the sediment to stand in near-vertical banks while being dredged. A dredge works more efficiently i

40、f the material wi maintain such a steep “face” during the dredging process. Muds and loose sands that flow like liquids lack this property. (f) The above statements apply to those dredging systems that remove material from the bottom through a pipeline by a pump. Such hydraulic dredges are not alway

41、s the most feasible dredging system to use because of space constraints, navigation requirements, dredging depth, sediment properties, or disposal options. Under some conditions, mechanical dredges, which include a grab bucket operated from a derrick, or a dipper dredge (power shovel) on a barge (Hu

42、ston 1970), may be more desirable. When mechanical dredges are used, looser sediments are usually dredged with a bucket and harder sediments with a dipper. (2) Properties important in environmental questions. (a) Recently, environmental problems associated with the handling and deposition of sedimen

43、t have received increased attention. These concerns most frequently arise from dredging operations, but can occur anytime sediment is introduced into the marine environment. The usual issues involve the burial of bottom- dwelling organisms, the blockage of light to bottom-dwelling and water-column o

44、rganisms, and the toxicity of the sediments. (b) The sediment property of most environmental consequence is size. Turbidity in the water column depends on the fall velocity of the sediment particles, which is a strong function of the grain size. Turbid waters can be carried by currents away from the

45、 immediate project site, blocking the light to organisms over a wide area and, as the sediments settle out, blanketing the bottom at a rate faster than the organisms can accommodate. Fine sediments (silts and clays) get greater scrutiny under environmental regulation because they produce greater and

46、 longer-lasting turbidity, which will impact larger areas of the seafloor than will 111-1-2 Coastal Sediment Properties Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-COE EC 1110-2-292 3515789 0827253 177 EC 1 11 0-2-292 31 Mar 98 coarser, sand-size

47、d material. The dredging of sand usually encounters less severe environmental objection, provided that there are few fines mixed with it and that the site has no prior toxic chemical history. (c) Environmental regulation is changing, and many regulatory questions are outside the usual experience of

48、coastal engineers. However, a basic coastal engineering contribution to facilitating the progress of a project through regulatory review is the early collection of relevant sediment samples from the site and obtaining accurate data on their size, composition, and toxicity. (3) Properties important i

49、n beach fills. (a) Beach fills have two primary functions: to provide temporary protection to upland property, and to increase temporarily the recreational space along the shore. Neither function can be well satisfied with sediment finer than sand. Because the recreational function is inhibited by material coarser than sand, and because fill coarser than sand is frequently less available, the primary beach fill