TRH20 (1990) The Structural Design, Construction and Maintenance of Unpaved Roads未铺路面的结构设计、施工和养护.pdf

TECHNICALRECOMMENDATIONSFORHIGHWAYS

DraftTRH20

THESTRUCTURALDESIGN,CONSTRUCTIONANDMAINTENANCEOF

UNPAVEDROADS

1990

ISBN0908381875

Pretoria,SouthAfrica,1990

Publishedby

DepartmentofTransport

POBox415

PRETORIA

0001

RepublicofSouthAfrica

forthe

CommitteeofStateRoadAuthorities

PRINTEDFEBRUARY1990

Printedinthe

RepublicofSouthAfrica

byV&RPrintingWorks(Pty)Ltd.

PRETORIA

PREFACE

TECHNICALRECOMMENDATIONSFORHIGHWAYS(TRH)arewrittenforthepractisingengineerand

describecurrent,recommendedpracticeinselectedaspectsofhighwayengineering.Theyarebasedon

SouthAfricanexperienceandontheresultsofresearchandhavethefullsupportoftheCommitteeofState

RoadsAuthorities(CSRA).

ThisdocumenthasbeenwrittenbyDrPPaige-GreenoftheDivisionofRoadsandTransportTechnology

undertheguidanceofasubcommitteeoftheHighwayMaterialsCommitteeconsistingof:

ProfATVisser–UniversityofPretoria,Pretoria(Chairman)

MrNvanderWalt–DOT,Pretoria

MrGDvanZyl–TPA,Pretoria

MrAThompson–NPA,Pietermaritzburg

MrEdeVilliers–CPA,CapeTown

MrJduPisani–OFSPA,Bloemfontein

MrSPoolman–SWADOT,Windhoek

MrTvanNiekerk–DBSA,HalfwayHouse

MrPAPienaar–JordaanandJoubert,Pietersburg.

Toconfirmitsvalidityinpractice,itwillbecirculatedindraftformforatrialperiodbeforebeingsubmittedto

theCSRAforapproval.Duringthisperiodyouarewelcometosendsuggestionsforimprovementtothe

ChiefMaterialsEngineer:DepartmentofTransport,POBox415,Pretoria,0001orTheDirector,DRTT-

CSIR,POBox395,Pretoria0001.Eventuallyareviseddocument,approvedbytheCSRA,willbeissuedas

afullTRHinbothlanguages.

SOMENEWDEFINITIONS

Gradingcoefficien