1、BRITISH STANDARD BS EN ISOSoil quality Determination of the waterretention characteristic Laboratory methodsICS13.080.40Incorporating corrigendum August 200911274:2014National forewordThis British Standard is the UK implementation of EN ISO 11274:2014. It is identical to ISO 11274:1998, incorporatin
2、g corrigendum August 2009. It supersedes BS ISO 11274:1998, which is withdrawn.The start and finish of text introduced or altered by corrigendum is indicated in the text by tags. Text altered by ISO corrigendum August 2009 is indicated in the text by .The UK participation in its preparation was entr
3、usted by Technical Committee EH/4, Soil quality.A list of organizations represented on this committee can be obtained on request to its secretary.The textual errors set out below were discovered when adopting the text of the International Standard. They have been reported to ISO in a proposal to ame
4、nd the text of the International Standard.Subclause 4.2, second paragraph. End of the first line should read “. pressure more positive than the first ”.Subclause 6.3 Delete “stopper the funnel and insert it” from the end of the final sentence. In addition, move the second sentence to the end of the
5、paragraph.Subclause 6.4, fourth sentence. Amend end of sentence to read “. is approximately equivalent to (h/10)”.Subclause 7.4, second paragraph, third sentence. The beginning should read “The pressure of the .”This publication does not purport to include all the necessary provisions of a contract.
6、 Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.BS EN ISO 11274:2014This British Standard, havingbeen prepared under thedirection of the Health andEnvironment Sector Committee,was published under theauthority of the
7、StandardsCommittee and comesinto effect on15 January 1999 The British Standards Institution 2014. Published by BSI Standards Limited 2014Amendments/corrigenda issued since publicationDate Comments 30 September 2011 Implementation of ISO corrigendum August 200931 May 2014 This corrigendum renumbers B
8、S ISO 11274:1998 as BS EN ISO 11274:2014.ISBN 978 0 580 82147 9EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 11274 March 2014 ICS 13.080.40 English Version Soil quality - Determination of the water-retention characteristic -Laboratory methods (ISO 11274:1998 + Cor 1:2009) Qualit du sol -
9、Dtermination de la caractristique de la rtention en eau - Mthodes de laboratoire (ISO 11274:1998 + Cor 1:2009) Bodenbeschaffenheit - Bestimmung des Wasserrckhaltevermgens - Laborverfahren (ISO 11274:1998 + Cor 1:2009) This European Standard was approved by CEN on 13 March 2014. CEN members are bound
10、 to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN
11、-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre ha
12、s the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Lu
13、xembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Bru
14、ssels 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 11274:2014 EEN ISO 11274:2014 (E) 3 Foreword The text of ISO 11274:1998, including Cor 1:2009 has been prepared by Technical Committee ISO/TC 190 “Soil quality” of the
15、International Organization for Standardization (ISO) and has been taken over as EN ISO 11274:2014 by Technical Committee CEN/TC 345 “Characterization of soils” the secretariat of which is held by NEN. This European Standard shall be given the status of a national standard, either by publication of a
16、n identical text or by endorsement, at the latest by September 2014, and conflicting national standards shall be withdrawn at the latest by September 2014. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall n
17、ot be held responsible for identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark
18、, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notic
19、e The text of ISO 11274:1998, including Cor 1:2009 has been approved by CEN as EN ISO 11274:2014 without any modification. BS EN ISO 11274:2014iiContentsPageForeword iiiIntroduction 11 Scope 12 Definitions 13 Guidelines for choice of method 24 Sampling 25 Determination of the soil water characterist
20、icusing sand, kaolin and ceramic suction tables 46 Determination of soil water characteristic usinga porous plate and burette 67 Determination of soil water characteristic bypressure plate extractor 78 Determination of soil water characteristic usingpressure membrane cells 109 Precision 12Annex A (i
21、nformative) Construction of suction tables 13 Annex B (informative) Bibliography Inside back coverFigure 1 Porous plate and burette apparatus 8Figure 2 Pressure plate extractor system 9Figure 3 Pressure membrane cell 11Figure A.1 Example of a drain system for sandand kaolin suction tables 13Figure A
22、.2 Example of a sand suction table 14Figure A.3 Example of a kaolin suction table 16Table 1 Recommended sample sizes (height diameter)for the different test methods 3Table 2 Examples of sands and silica flour suitable forsuction tables 4Table A.1 Pressure equivalents 15Descriptors: Soils, quality, t
23、ests, soil testing, laboratory tests, determination, water retention.ISO 11274:1998 (E) BSI 2011BS EN ISO 11274:2014iv blank1IntroductionSoil water content and matric pressure are related to each other and determine the water-retention characteristics of a soil. Soil water which is in equilibrium wi
24、th free water is at zero matric pressure (or suction) and the soil is saturated. As the soil dries, matric pressure decreases (i.e.becomes more negative), and the largest pores empty of water. Progressive decreases in matric pressure will continue to empty finer pores until eventually water is held
25、in only the finest pores. Not only is water removed from soil pores, but the films of water held around soil particles are reduced in thickness. Therefore a decreasing matric pressure is associated with a decreasing soil water content5,6. Laboratory or field measurements of these two parameters can
26、be made and the relationship plotted as a curve, called the soilwater-retention characteristic. The relationship extends from saturated soil (approximately0kPa) to oven-dry soil (about 106 kPa).The soil water-retention characteristic is different for each soil type. The shape and position of the cur
27、ve relative to the axes depend on soil properties such as texture, density and hysteresis associated with the wetting and drying history. Individual points on the water-retention characteristic may be determined for specific purposes.The results obtained using these methods can be used, for example:
28、to provide an assessment of the equivalent pore size distribution (e.g.identification of macro- and micropores);to determine indices of plant-available water in the soil and to classify soil accordingly (e.g.for irrigation purposes);to determine the drainable pore space (e.g.for drainage design, pol
29、lution risk assessments);to monitor changes in the structure of a soil (caused by e.g.tillage, compaction or addition of organic matter or synthetic soil conditioners);to ascertain the relationship between the negative matric pressure and other soil physical properties (e.g.hydraulic conductivity, t
30、hermal conductivity);to determine water content at specific negative matric pressures (e.g.for microbiological degradation studies);to estimate other soil physical properties (e.g.hydraulic conductivity).1 ScopeThis International Standard specifies laboratory methods for determination of the soilwat
31、er-retention characteristic.This International Standard applies only to measurements of the drying or desorption curve.Four methods are described to cover the complete range of soil water pressures as follows:a) method using sand, kaolin or ceramic suction tables for determination of matric pressure
32、s from0kPa to 50kPa;b) method using a porous plate and burette apparatus for determination of matric pressures from0kPa to 20kPa;c) method using a pressurized gas and a pressure plate extractor for determination of matric pressures from 5kPa to 1500kPa;d) method using a pressurized gas and pressure
33、membrane cells for determination of matric pressures from 33kPa to 1500kPa.Guidelines are given to select the most suitable method in a particular case.2 DefinitionsFor the purposes of this International Standard, the following definitions apply.2.1 soil water-retention characteristicrelation betwee
34、n soil water content and soil matric head of a given soil sample2.2 matric pressureamount of work that must be done in order to transport, reversibly and isothermally, an infinitesimal quantity of water, identical in composition to the soil water, from a pool at the elevation and the external gas pr
35、essure of the point under consideration, to the soil water at the point under consideration, divided by the volume of water transported2.3 water content mass ratiowmass of water evaporating from the soil when dried to constant mass at105 C, divided by the dry mass of the soil (i.e.the ratio between
36、the masses of water and solid particles within a soil sample)ISO 11274:1998 (E) BSI 2011BS EN ISO 11274:201422.4 water content volume fractionvolume of water evaporating from the soil when dried to constant mass at105 C, divided by the original bulk volume of the soil (i.e.the ratio between the volu
37、me of liquid water within a soil sample and the total volume including all pore space of that sample)NOTE 1The soil water-retention characteristic is identified in the scientific literature by various names including soil water release curve, soil water-retention curve, pF curve and the capillary pr
38、essure-saturation curve. Use of these terms is deprecated.NOTE 2The pascal is the standard unit of pressure but many other units are still in use. Table A.1 provides conversions for most units.NOTE 3Sometimes suction is used instead of pressure to avoid the use of negative signs (see Introduction).
39、However, this term can cause confusion and is deprecated as an expression of the matric pressure.NOTE 4For swelling and shrinking soils, seek the advice of a specialist laboratory since interpretation of water-retention data will be affected by these properties.3 Guidelines for choice of methodGuide
40、lines are given below to help select the most suitable method in a particular case.3.1 Sand, kaolin or ceramic suction tables for determination of pressures from0kPato 50kPaThe sand, kaolin and ceramic suction table methods are suitable for large numbers of determinations at high pressures on cores
41、or aggregates of different shapes and sizes. Analyses on samples of a wide range of textures and organic matter contents can be carried out simultaneously since equilibration is determined separately for each core. The suction table methods are suitable for a laboratory carrying out analyses on a ro
42、utine basis and where regular equipment maintenance procedures are implemented.3.2 Porous plate and burette apparatus for determination of pressures from0kPato 20kPaThe porous plate and burette apparatus allows analysis of only one sample at a time, and several sets of equipment are therefore necess
43、ary to enable replication and full soil profile characterization. The method is particularly suited to soils with weak structures and sands which are susceptible to slumping or slaking, since minimal sample disturbance occurs. Capillary contact is not broken during the procedure and all samples, par
44、ticularly soils with higher organic matter content or sandy textures, will equilibrate more rapidly using this technique. This is a simple technique suitable for small laboratories.3.3 Pressure plate extractor for determination of pressures from 5kPa to 1500kPaThe pressure plate method can be used f
45、or determinations of all pressures to 1500kPa. However, different specifications of pressure chambers and ceramic plates are required for the range of pressures, e.g.0kPa to 20kPa, 20kPa to 100kPa and 100kPa to 1500kPa. Themethodis, however, best suited to pressures of 33kPa or lower, since air entr
46、apment at high negative pressures can occur. It is preferable that soils with similar water-release properties are analysed together to ensure equilibration times are approximately the same, though in practice it may be difficult. Sample size is usually smaller than for the previous two methods and
47、therefore the technique is less suitable for heterogeneous soil horizons, or for those with a strong structural composition. Analysis of disturbed soils is traditionally carried out using this method.3.4 Pressure membrane cells for determination of pressures from 33kPato 1500kPaThe pressure membrane
48、 cell should only be used for pressures below 33kPa. Capillary contact at higher pressures is not satisfactory for this method. The method is appropriate for all soil types though the use of double membranes is recommended for coarse (sandy) textured soils. Sample size can be selected (according to
49、the size of the pressure cell) to take into account soil structure. Different textures can be equilibrated separately using a suite of cells linked to one pressure source.4 Sampling4.1 General requirementsIt is essential that undisturbed soil samples are used for measurement at the high matric pressure range0kPa to 100kPa, since soil structure has a strong influence on water-retention properties. Use either undisturbed cores or, if appropriate, individual peds for low matric pressure methods (600 m 1 1 1 0200 m to600 m 61 8 1 0100 m to200 m 36 6
