1、A807/A807M-19REGULARBACKFILLLARGEROCKLEVEL LIFTS OFSTRUCTURAL BACK-FILL PLACED INMINIMUM GREATER OFD/80R12in.300mmLAYERS 6 in.TO 12 inTO 300 mm)AND THENCOMPACTEDSTRUCTURAL BACK-FILL COMPACTEDUNDER HAUNCHESFINE-GRADEDTRENCHFOUNDATIONFOR NARROW TRENCH,W 24 IN.600 mmSHAPE REDDING TO PIIPE INVERT FOR AW
2、IDTH OF D/2.UNLESS CLSM IS USEDFOR STRUCTURAL BACKFILL OR BEDDINGFIG.1 Typical Trench InstallationLEVEL LIFTS OF STRUCTURALBACKFILL,PLACED IN LAYERS6 in.TO 12 in.150 mm TO 300 mmREGULARTHICK,AND THEN COMPACTEDBACKFILLSLOPE OFEMBANKMENTSEE TABLE 1MINIMUM GREATER OFD/8 OR 12 IN.300 mm-2D MIN.727802772
3、702702102027280207720200270878702780202027872778787FINE-GRADEDFOUNDATIONCOMPACTED UNDER HAUNCHESFIG.2 Typical Embankment(Projection)Installation3.2.1 arch,n-a part circle shape spanning an open invert3.2.7 underpass,n-a high arch shape with an approximatebetween the footings on which it rests.semici
4、rcular crown,large-radius sides,small-radius corners3.2.2 bedding,n-the earth or other material on which abetween sides and invert,and large-radius invert.pipe is supported.4.Significance and Use3.2.3 haunch,n-the portion of the pipe cross sectionbetween the maximum horizontal dimension and the top
5、of the4.1 Structural plate structures function structurally as abedding.flexible ring that is supported by and interacts with the3.2.4 invert,n-the lowest point on the pipe cross section;compacted surrounding soil.The soil placed around the struc-also,the bottom portion of a pipe.ture is thus an int
6、egral part of the structural system.It istherefore important to ensure that the soil structure is made up3.2.5 pipe,n-a conduit having full circular shape;also,inof acceptable material and is well constructed.Field verifica-a general context,all structure shapes covered by this practice.tion of soil
7、 structure acceptability using Test Methods D1556,3.2.6 pipe-arch,n-an arch shape with an approximateD2167,D6938,or D2937,as applicable,and comparing thesemicircular crown,small-radius corners,and large-radiusresults with either Test Methods D698 or D1557,in accordanceinvert.with the specifications for each project,is the most common
