BS 1377-5-1990 Methods of test for soils for civil engineering purposes - Compressibility permeability and durability tests《土木工程用土壤试验方法 第5部分 可压缩性、渗透性和耐用性试验》.pdf

《BS 1377-5-1990 Methods of test for soils for civil engineering purposes - Compressibility permeability and durability tests《土木工程用土壤试验方法 第5部分 可压缩性、渗透性和耐用性试验》.pdf》由会员分享，可在线阅读，更多相关《BS 1377-5-1990 Methods of test for soils for civil engineering purposes - Compressibility permeability and durability tests《土木工程用土壤试验方法 第5部分 可压缩性、渗透性和耐用性试验》.pdf（40页珍藏版）》请在麦多课文档分享上搜索。

1、BRITISH STANDARD BS 1377-5: 1990 Incorporating Amendment No. 1 Methods of test for Soils for civil engineering purposes Part 5: Compressibility, permeability and durability tests UDC 621.131.3:631.4.625:620.1BS1377-5:1990 This British Standard, having been prepared under the direction of the Road En

2、gineering Standards Policy Committee, waspublished under the authority of the Board of BSI and comes intoeffect on 30 April 1990 First published in 1948 First published in metric 1975 Second edition April 1990 BSI 12-1998 The following BSI references relate to the work on this standard: Committee re

3、ference RDB/38 Draft for comment 88/14766 DC ISBN 0 580 18030 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Road Engineering Standard Policy Committee (RDB/-) to Technical Committee RDB/38, upon which the following bodies were repres

4、ented: Association of Consulting Engineers British Civil Engineering Test Equipment Manufacturers Association County Surveyors Society Department of the Environment (Property Services Agency) Department of the Environment (Building Research Establishment) Department of Transport Department of Transp

5、ort (Transport and Road Research Laboratory) Coopted members Amendments issued since publication Amd. No. Date of issue Comments 8260 November 1994 Indicated by a sideline in the marginBS1377-5:1990 BSI 12-1998 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definit

6、ions 1 3 Determination of the one-dimensional consolidation properties 1 4 Determination of swelling and collapse characteristics 8 5 Determination of permeability by the constant-head method 11 6 Determination of dispersibility 15 6.1 General 15 6.2 Pinhole method 15 6.3 Crumb method 17 6.4 Dispers

7、ion method 18 7 Determination of frost heave 19 Appendix A Typical test data and calculation forms 29 Figure 1 Section of a typical consolidation cell 20 Figure 2 Laboratory consolidation curve: logarithm of time fitting method 21 Figure 3 Laboratory consolidation curve: square root of time fitting

8、method 22 Figure 4 Temperature correction curve for coefficient of consolidation and permeability 23 Figure 5 Section of a typical constant-head permeability cell 24 Figure 6 Arrangement of apparatus for constant-head permeability test 25 Figure 7 Section of pinhole test apparatus: a) arrangement fo

9、r test b) details of nipple 26 Figure 8 Flowchart for pinhole test procedure 27 Figure 9 Typical results from dispersion (double hydrometer) test 28 Table 1 Suggested initial pressures for consolidation test 5 Table 2 Classification of soils from pinhole test data 18 Publications referred to Inside

10、back coverBS1377-5:1990 ii BSI 12-1998 Foreword This Part of BS 1377 has been prepared under the direction of the Road Engineering Standards Policy Committee. It is a part revision of clause 5 of BS1377:1975 which is deleted by amendment. BS 1377:1975 which has now been withdrawn is replaced by the

11、following Parts of BS 1377:1990: Part 1: General requirements and sample preparation; Part 2: Classification tests; Part 3: Chemical and electro-chemical tests; Part 4: Compaction-related tests; Part 5: Compressibility, permeability and durability tests; Part 6: Consolidation and permeability tests

12、in hydraulic cells and with pore pressure measurement; Part 7: Shear strength tests (total stress); Part 8: Shear strength tests (effective stress); Part 9: In-situ tests. Reference should be made to Part 1 for further information about each of the Parts. The following test procedures, additional to

13、 those described in the 1975 standard, have been introduced: a) swelling pressure and settlement on saturation measurements in an oedometer consolidation apparatus; b) determination of the coefficient of permeability of sands by the constant head permeameter method; c) determination of the susceptib

14、ility to internal erosion of clay soils, using three empirical tests: 1) the pinhole method; 2) the crumb method; 3) the dispersion (sedimentation) method. d) determination of the susceptibility to frost heave, for which reference is made to BS812-124. Some amendments have been made to the one-dimen

15、sional oedometer consolidation test, which is nevetheless the same in principle as the test described in the 1975 standard. It has been assumed in the drafting of this British Standard that the execution of its provisions is entrusted to appropriately qualified and experienced personnel. A British S

16、tandard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cov

17、er, an inside front cover, pages i and ii, pages 1 to 34, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BS1377-5:1990 BSI 12-1998 1 1 Scope Th

18、is Part of BS 1377 describes methods of test for the determination of the consolidation characteristics of soils when subjected to changes in the applied effective stress, the permeability characteristics of sands, the susceptibility of clays to internal erosion by water, and the susceptibility of s

19、oils to heave in freezing conditions. Reference is made to some of the classification tests described in BS 1377-2, and to some of the methods of soil compaction described in BS 1377-4. Reference is made to Part 1 for general requirements that are relevant to all Parts of this British Standard and f

20、or methods of preliminary preparation of soil and specimens for testing. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this Part of BS1377 the definitions given in BS1377-1 apply, together with the following. 2.

21、1 erodibility (dispersibility) erosion of fine-grained soils by a process in which individual clay particles go into suspension in practically still water 2.2 dispersive soils soils that are erodible in still water. They usually contain a preponderance of sodium cations in the pore water 3 Determina

22、tion of the one-dimensional consolidation properties 3.1 General 3.1.1 Principle. This method covers the determination of the magnitude and rate of the consolidation of a saturated or near-saturated specimen of soil (see note 1) in the form of a disc confined laterally, subjected to vertical axial p

23、ressure, and allowed to drain freely from the top and bottom surfaces. The method is concerned mainly with the primary consolidation phase, but it can also be used to determine secondary compression characteristics. In this test the soil specimen is loaded axially in increments of applied stress. Ea

24、ch stress increment is held constant until the primary consolidation has ceased. During this process water drains out of the specimen, resulting in a decrease in height which is measured at suitable intervals. These measurements are used for the determination of the relationship between compression

25、(or strain) or voids ratio and effective stress, and for the calculation of parameters which describe the amount of compression and the rate at which it takes place. NOTE 1The method described covers the procedure and technique for consolidation tests on naturally deposited soils taken undisturbed f

26、rom the ground in the form of cores or blocks. The term sample denotes the soil submitted to the laboratory for testing, and the term specimen refers to a portion of the sample upon which the consolidation test is performed. NOTE 2Data obtained from this type of consolidation test, if carried out on

27、 representative undisturbed samples of good quality, enable the amount of settlement under a structure to be estimated. Values of the coefficient of consolidation can also be calculated from which an indication of a theoretical rate of settlement can be derived. However the predicted settlement time

28、s can be greatly in excess of those observed in practice and should be treated with caution. NOTE 3The small size of the specimen normally used for this test frequently does not represent adequately the fabric features found in many natural deposits, which collectively dominate the drainage characte

29、ristics of the soil en masse and therefore the rate of settlement in-situ. The requirements of Part 1 of this standard, where appropriate, shall apply to this test method. 3.1.2 Environmental requirements. The test shall be carried out in an area that is free from significant vibrations and other me

30、chanical disturbance. The apparatus shall be sited away from the effects of local sources of heat, direct sunlight and draughts. The test shall be carried out in a laboratory in which the temperature is maintained constant to within4 C in compliance with 6.1 of BS 1377-1:1990. 3.2 Apparatus 3.2.1 Co

31、nsolidation apparatus 3.2.1.1 The consolidation apparatus, known as the oedometer, shall be of the fixed ring type and shall consist essentially of the features described in3.2.1.1.1 to 3.2.1.1.5. 3.2.1.1.1 A consolidation ring which shall completely and rigidly support and confine the soil specimen

32、 laterally. The ring shall be of corrosion-resistant metal. The ring shall be provided with a cutting edge to facilitate the preparation of the specimen. The inner surface of the ring shall be smooth. NOTE 1The inner surface of the ring may be coated with a low friction material to minimize wall fri

33、ction. Alternatively silicone grease or petroleum jelly may be used.BS1377-5:1990 2 BSI 12-1998 The diameter of the consolidation ring shall be determined primarily by the nominal sizes of undisturbed tube samples received for test but also with regard to the character of the soil and the maximum si

34、ze of particles present in the sample. The inside diameter of the ring used for fine silts and clay soils shall be at least 6 mm smaller than the undisturbed tube sample to permit trimming off no less than 3 mm of soil all around which may have been disturbed during the sampling operation. For coars

35、e silt and sand containing some clay (seenote2), also for soils which contain numerous inclusions such as small stones or hard lumps, (e.g.boulder clay, marl, chalk), and for soils which break or deform badly on extrusion from the sampling tube, the inside diameter of the ring shall be as close as p

36、ossible to the size of the tube sample because of the difficulty of trimming such specimens (see note3). The inside diameter shall be not less than 50 mm and not greater than 105 mm. NOTE 2The method described is considered unsuitable for cohesionless sands and silts and for such soils a test at zer

37、o lateral strain (K ocompression test) in a triaxial apparatus is recommended. NOTE 3The inside diameters of some sampling tubes are nominal and it is thus impracticable in such cases to provide a consolidation ring with an inside diameter of the same size as the soil sample. The height of the ring

38、shall be not less than 18 mm and not more than 0.4 times the internal diameter. NOTE 4The selection of a specimen conforming with this range of thickness to diameter ratios is recommended as a reasonable compromise to limit as far as possible the effect of side friction between the specimen and the

39、wall of the ring, and at the same time to keep the effect of specimen disturbance during preparation to a reasonable level. A ring 75 mm in diameter and20 mm high has been found to be satisfactory for silt and clay soils. 3.2.1.1.2 Corrosion-resistant porous plates for placing at the top and bottom

40、surfaces of the test specimen. Their porosity shall allow free drainage of water throughout the test but shall prevent intrusion of soil into their pores. (see 3.4.1). The thickness of the plates shall be sufficient to prevent breaking under load, and the material shall be of negligible compressibil

41、ity under the loads applied during the test. The upper and lower surfaces shall be plane, clean and undamaged. NOTE 1Plates of bauxilite or sintered bronze 6 mm to 13 mm thick have been found to be suitable. The diameter of the top porous plate shall be about0.5 mm smaller than the inside diameter o

42、f the consolidation ring, in order to permit free compression of the soil specimen. A taper towards the upper edge is permissible to minimize the danger of binding, should tilting occur. The bottom porous plate shall be large enough to support the consolidation ring and its specimen adequately. NOTE

43、 2The clearance should not be too great otherwise serious penetration of the soil between the side of the porous plate and the consolidation ring may take place; clearances in diameter from about 0.25 mm to about 0.75 mm have been found to be satisfactory. 3.2.1.1.3 A consolidation cell of suitable

44、corrosion-resistant material within which is placed the consolidation ring containing the sample. The cell shall accept the consolidation ring with a push fit. The specimen is held between the top and bottom porous plates and rests centrally on the base of the cell. Load is applied to the specimen t

45、hrough a rigid, centrally mounted, corrosion-resistant loading cap fitted with a central seating. The principal features of the cell are illustrated in Figure 1(a). The cell shall be capable of being filled with water to a level higher than the top of the upper porous plate. The materials comprising

46、 the cell and the components which fit into it shall not be corrodible by electro-chemical reaction with each other. 3.2.1.1.4 A dial gauge or a displacement transducer referred to as the compression gauge. The gauge shall be supported for measuring the vertical compression or swelling of the specim

47、en throughout the test. It shall be readable to 0.002 mm and shall have a travel of at least 10 mm. Where more than12mm travel is required a readability of0.01mm is permissible. 3.2.1.1.5 A loading device having a rigid bed for supporting the consolidation cell. The device shall enable a vertical fo

48、rce to be applied axially in increments to the test specimen through a loading yoke. Each force increment shall be maintained constant by a stress-control method while permitting increasing vertical compression of the test specimen during the consolidation test. The vertical force applied to the tes

49、t specimen shall produce calculated intensities of pressure within an accuracy of 1 % or 1 kPa, whichever is the greater. The apparatus shall be capable of accommodating a compression of at least 75 % of the specimen thickness. A counterbalanced lever system, using calibrated weights in increments, is the method commonly employed for applying the vertical force to the test specimen, and the test procedure described in this specification is applicable to this type of stress-control loading. The force applied to the test specimen shall be a