1、Designation: D7208 14Standard Test Method forDetermination of Temporary Ditch Check Performance inProtecting Earthen Channels from Stormwater-InducedErosion1This standard is issued under the fixed designation D7208; the number immediately following the designation indicates the year oforiginal adopt
2、ion or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the guidelines, requirements,and procedures for e
3、valuating the ability of temporary ditchcheck systems to protect earthen channels from stormwater-induced erosion. Critical elements of this protection are theability of the temporary ditch check to:1.1.1 Slow or pond runoff, or both, to encouragesedimentation, thereby reducing soil particle transpo
4、rt down-stream;1.1.2 Trap soil particles up stream of structure; and1.1.3 Decrease soil erosion.1.2 This test method utilizes full-scale testing procedures,rather than reduced-scale (bench-scale) simulation, and ispatterned after conditions typically found on construction sitesat the conclusion of e
5、arthwork operations, but prior to the startof revegetation work. Therefore this test method considers onlyunvegetated conditions.1.3 This test method provides a comparative evaluation of atemporary ditch check to baseline bare soil conditions undercontrolled and documented conditions.1.4 All observe
6、d and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026 unless superseded by this standard.1.4.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as theindustry standard. In add
7、ition, they are representative of thesignificant digits that should generally be retained. The proce-dures used do not consider material variation, purpose forobtaining the data, special purpose studies, or any consider-ations for the users objectives; and it is common practice toincrease or reduce
8、significant digits of reported data to com-mensurate with these considerations. It is beyond the scope ofthis standard to consider significant digits used in analysismethods for engineering design.1.5 The values stated in SI units are to be regarded asstandard. The values given in parentheses are ma
9、thematicalconversions to inch-pound units, which are provided forinformation only and are not considered standard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate s
10、afety and health practices and determine the applica-bility of regulatory limitations prior to use. Also, the user mustcomply with prevalent regulatory codes, such as OSHA (Oc-cupational Health and Safety Administration) guidelines, whileusing the test method.2. Referenced Documents2.1 ASTM Standard
11、s:2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD698 Test Methods for Laboratory Compaction Character-istics of Soil Using Standard Effort (12 400 ft-lbf/ft3(600kN-m/m3)D3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in
12、Engineering Design and ConstructionD6026 Practice for Using Significant Digits in GeotechnicalDataD6460 Test Method for Determination of Rolled ErosionControl Product (RECP) Performance in ProtectingEarthen Channels from Stormwater-Induced Erosion3. Terminology3.1 DefinitionsFor definitions of terms
13、 used in this testmethod, see Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 temporary ditch check (in erosion control), nanon-permanent barrier consisting of rocks, straw bales, excel-sior logs, wattles, lumber, rock bags, interlocking pre-cast1This test method is under t
14、he jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.25 on Erosion andSediment Control Technology.Current edition approved Jan. 1, 2014. Published January 2014. Originallyapproved in 2006. Last previous edition approved in 2006 as D7208 06. DOI:10
15、.1520/D7208-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor
16、Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1concrete blocks, or other materials installed or constructedacross a drainage way, swale, or other ephemeral waterway toreduce flow velocity, decrease erosion, and promote soilretention.3.2.2 trapezoidal test channel, nan earthen ch
17、annel usedto test erosion control products shaped such that the bottom isflat with sides greater than 90 angle in relation to the bottomof the channel.4. Summary of Test Method4.1 The performance of a temporary ditch check in reducingstormwater-induced erosion is determined by subjecting thematerial
18、 to simulated stormwater flow in a controlled anddocumented environment.4.2 Key elements of the testing process include:4.2.1 Calibration of the stormwater simulation equipment;4.2.2 Preparation of the test channel;4.2.3 Documentation of the temporary ditch check(s) to betested;4.2.4 Installation of
19、 the temporary ditch check(s);4.2.5 Performance of the test;4.2.6 Collection of hydraulic, topographical, and associateddata;4.2.7 Analysis of the resultant data; and4.2.8 Reporting.5. Significance and Use5.1 This test method evaluates a system of temporary ditchchecks and their means of installatio
20、n to:5.1.1 Reduce soil loss and sediment concentrations instormwater runoff under conditions of varying channel condi-tions and soil type; and5.1.2 Improve water quality exiting the area disturbed byearthwork activity by reducing suspended solids.5.2 This test method models and examines conditions t
21、ypi-cally found on construction sites involving earthworkactivities, including: highways and roads; airports; residential,commercial and industrial developments; pipelines, mines, andlandfills; golf courses; etc.5.3 This test method is a performance test. It is a compara-tive tool for evaluating the
22、 erosion control characteristics ofdifferent temporary ditch checks and can be used for qualitycontrol to determine product conformance to project specifi-cations. Take caution when comparing results from differentlaboratories because information about between-laboratoryprecision is incomplete and s
23、light differences in soil and otherenvironmental and geotechnical conditions may affect tempo-rary ditch check performance. Unique project-specific condi-tions should be taken into consideration.NOTE 1The quality of the result produced by this standard isdependent on the competence of the personnel
24、performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D3740 are generally considered capable of competentand objective testing/sampling/inspection/etc. Users of this standard arecautioned that compliance with Practice D3740 does not in its
25、elf assurereliable results. Reliable results depend on many factors; Practice D3740provides a means of evaluating some of those factors.6. Apparatus6.1 Test ChannelThe earthen trapezoidal test channel shallbe a minimum of 18 m (59 ft) in length. The channel shall beconstructed to approximatelya5%slo
26、pe. The channel shall beconstructed to a 0.6 m (2.0 ft) bottom width with 2H:1V sideslopes prior to testing. The test channel shall have a way ofmeasuring water discharging in to the channel. A weir issuitable this purpose.6.2 Water Delivery SystemThe water delivery system shallinclude pump(s), pipi
27、ng, channels, and water controlstructures, as necessary, to achieve the desired hydraulicconditions. The water control structures shall regulate the flowand to direct it into the desired test channel. The water deliverysystem shall be constructed such that turbulence at the entranceto the test chann
28、el is minimized. Use of flow straighteners (forexample, tube racks or vanes) will reduce turbulence andachieve uniform flow conditions. For this purpose, use a directflow system (that is, controlled flow diverted from a naturalwaterway). The water delivery system in Fig. 1 shows anexample of a close
29、d-loop water delivery system.6.3 Total Station SystemThe total station system is astandard surveying instrument that is capable of measuringvertical and horizontal angles, and distance, simultaneously todetermine measurement point coordinates (that is, X, Y and Zaxis) and that uses an internal data
30、logger to store thisinformation for future use. Instead of a total station system,manual surveying equipment may be used providing it suppliesequivalent accuracy. Periodic calibration and certification ofthis equipment shall be performed.6.4 Velocity ProbeA velocity probe capable of measuringpoint v
31、elocities to an accuracy of 60.03 m/s (60.10 ft/s) shallbe used to identify flow conditions during test operation.Acceptable types of probes include electromagnetic, spinningcup, propeller, and static tube devices. Periodic calibration andcertification of this equipment shall be performed.6.5 Miscel
32、laneousOther miscellaneous equipment in-cludes: meteorological equipment (wind speed, temperature,precipitation), and cameras or video recorders.7. Reagents7.1 Water SourceAny water source shall be suitable fortesting provided that it is not sediment laden or containsdeleterious materials that could
33、 impair the operation of thepumps.8. Calibrations8.1 Perform determination of the water delivery systemdischarge (Q). Begin calibration of the water delivery systemwhen a steady-state flow is achieved.8.2 For open-channel water delivery systems, measure thedepth of water flowing into the test channe
34、l. Measure thevelocity in the supply channel using a velocity probe in themeasurement location shown in Fig. 2.9. Procedure9.1 Trapezoidal Test Channel Preparation:D7208 1429.1.1 Construct earthen test channels using conventionalearthwork placement techniques similar to procedures outlinedin Test Me
35、thod D6460 for trapezoidal channels. Performcompaction of channel bed material to create a stable subgrade.9.1.2 Plate the channel surface with a minimum 45 cm (18in.) thick veneer of soil. General soil types to be used fortesting shall be loam, clay, and sand. Target grain sizes andplasticity indic
36、es are included in Table 1. Place the veneer in 15FIG. 1 Typical Water Delivery SystemFIG. 2 Typical Channel Cross-SectionD7208 143cm (6 in.) lifts and compact to 90 6 3 % of standard Proctordensity in accordance with Test Method D698.9.1.3 Excavate the channels to a trapezoidal cross-sectionwith a
37、61 6 2 cm (2.0 6 0.07 ft) bottom width and 2H:1V sideslopes. The test channels shall be a minimum of 18.3 m (60.0ft) in length to allow sufficient distance between temporaryditch check structures during testing. Bed slope shall beapproximately 5 %. Fig. 3 shows a typical channel profile andFig. 2 sh
38、ows a typical channel cross-section.9.1.4 Begin the test reach far enough below the inlet to thechannel to ensure flow is uniform and extend 12 6 0.3 m to (396 1 ft) downstream from that point. Establish benchmarks oneither side of the channel at each end of the test reach and at 1.56 0.1 m (5.0 6 0
39、.3 ft) intermediate intervals (nine cross-sections total).9.1.5 Loosen the soil veneer in the test reach and 1.5 6 0.1m (5.0 6 0.3 ft) upstream and downstream of the test reach toa depth of approximately 10 6 2 cm (4.0 6 0.8 in.) using atiller or other appropriate tools. Rake the tilled channel smoo
40、thwith a steel hand rake and compact. Repair depressions, voids,soft or uncompacted areas before testing can commence. Also,free the channel from obstruction or protrusions, such as roots,large stones or other foreign material.9.1.6 If the channel has been used previously for a testseries, discard t
41、he soil carried out of the channel, and obliterateany rills and gullies. Spread new soil of the same type acrossthe channel and blend (rake or tilled) into the surface.9.2 Pre-Test Documentation:9.2.1 Maintain a test folder for each test cycle, includinginformation on:9.2.1.1 Site conditions;9.2.1.2
42、 Geotechnical and soil conditions;9.2.1.3 Meteorological data;9.2.1.4 Temporary ditch check product type, description,and installation procedure; and9.2.1.5 Photo documentation.9.2.2 Include the following subjective site information:general visual conditions of the channel to be tested; generalmeteo
43、rological information; channel treatment; photographs orvideotape, or both, and any supplemental information that isnot included in the following sections, but is thought to be ofsignificance to the test.9.2.3 Include the following geotechnical and soils informa-tion: soil classification Unified Soi
44、l Classification System(USCS) or USDA classification system, or both; StandardProctor moisture-density relationship; “K” factor; and grada-tion (including hydrometer test for the P200fraction).9.2.4 Include the following meteorological information: alldata from the on-site weather station at the tim
45、e of the test (thatis, ambient air temperature, wind speed and precipitation).9.2.5 Include the following product type and descriptioninformation: manufacturer name; product name; description;specifications; size, and; a sample of the material, if practical.9.3 Test Set-Up:9.3.1 Install the maximum
46、number of temporary ditchcheck(s) in the 12.2 6 0.1 m (40.0 6 0.3 ft) test channel aftercalibration has been completed and the test channel has beenprepared. Document the installation methodology for thetemporary ditch check(s) including: orientation on the bed andside slopes (longitudinal or latera
47、l); placement (which sidefaces up); termination details; joint details; spacing betweentemporary ditch checks if more than one is to be tested, and;anchor type and installation pattern. Place the temporary ditchcheck(s) across the channel bottom perpendicular to the flowdirection and extend it up th
48、e side slopes far enough so pondedwater cannot erode around the temporary ditch check. If morethan one temporary ditch check is to be tested, spacing shallfollow manufacturer recommendations or ditch check spacingequation (see Section 10).9.3.2 Measure the elevation of the channel surface with theto
49、tal station equipment using the reference benchmarks and astringline between opposing benchmarks. Take elevation mea-surements for each test cross-section (nine total) at the loca-tions shown in Fig. 2. Elevation measurements for additionalcross-sections directly in front and behind each temporaryditch check shall also be taken to measure deposition and/orscour directly adjacent to ditch check structure. To allowmeasurement of the channel surface, a steel tip extension(“stinger”) may need to be attached to the base of theTABLE 1 Target Grain Sizes and Plasticity Ind
