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I <br /> � tiuil n;iil; i�pi�alh cun;i,i ol'::6 tu �'I� thrc:idc�l st�cl bur; f'=� t�� I-' : inch di;imetcr). Ihc stccl bur, :uc <br /> placed in a- tu 13-inch-di�inet�r holes drilled at �n�les t��pic:ilh' rum�ing �ium 10 to �� degrces belo�c <br /> I horizontal. Centralizcrs are used [o cent�r[he steel b:irs in the holes. Once thc steel bars are installed. !hc <br /> { hules are grouted usinu cement �rout or concrete. Post ��rout tubes can be installed widi the steel bars to <br /> incrcase [he bond strength bch�cen tlic erout .md die soil. Post �routin�� consists ol'injectcd erout under <br /> � high pressurc throueh holes plattd in the post�rout tube ane to two d:rvs a�ier ini[ial grout placer.�ent. <br /> Thc soils t}�picall�� are rcquir:d ro have an adequate standup time ([o allo�c placemen[ of tlte steel �cire <br /> � nxsh ❑nd/or reinforein!_ burs to be installed and the shoterete to be pl;rced). Soils ��'hich ha��c shurt <br /> standup timcs arc problcmatic (o;soil nailinc:md may rcquire dtc usc of vertical cicmcnu. <br /> Prclimin:uti• Ucsign Rccommeud:Uions. �1'e recommend [hc follo���ing for prdiminan dc,iui purp�,:�'>: <br /> � • A soil nail erid pnttern ol about 6 feet by 6 �cet. <br /> . A soil n�iil Icngd� ot thrcoquarters o(the wall hei!,ht (but not I�ss than 10 fceQ. inclined n[ about <br /> � I� to 20 dc��rccs from dic I�orimnml. <br /> � • �\ preliminar� allowahlc ,idlicsiun �aluc of I ksf Ibr till soils, 2 ksf fbr �,lacial tilL and I.� ksf I��r <br /> thc advance ouhva;h and \1'hidbcy I'ornta[ion (utilizing a 6 to 1? inch di.mictcr nail). <br /> � . Strips o( draina��e material installed behind du shoterete to relieve hcdro;tatic pressur�<. <br /> I �\ddilional Jrainagc provisions m.iy be necess�ry should signiticant eround«atcr be encountcrc�l <br /> during�hc cxc;��:uion. <br /> � . It m;��� bc ncccssar�� ro install ��crtiral clumcnts ���ithin dic upper portion of thc soil nail �vall in <br /> ' ordcr to impro�c facc stabilih �cithin thc �ill soils or to act a, a c;mtilc�cr «all w mcct nail <br /> cicarancc requircm�nts where buried utilitics are present. Vertical elements typically cuiuist o( <br /> � vcrtical stecl bars or small bcams pl,�ced in drilled holes lucat�d alon� the ��'all �li��nment and <br /> bacl:filled with Ican concrete. l�he s'pacing of��ertical elemen;s typieally r;mces from 3 to d feet <br /> on c�nter. "fhe necd fin �crtic:il cicments shoulJ bc further evaluated during the desi�=n of the soil <br /> inail wall, if scl�cted. <br /> fhc �ill ;u thc sitc and ihe fill associated ��ith utilities locatcd bchind thc ��alls ��ill uffect the soil nail <br /> ) dcsign. 'I��pically, the soil n:iil sp:uing is tighter or the suil nails are lun�,er, or both. ���here �ill or luoser <br /> '1 nati�-e soils are present comp;u'ed to �vhere stiff to hard silt and clay ur dense to vcry dense sanJ and <br /> er;�ccl soils arc present. <br /> 1 Difficulties nssuciated �cith Gice stability and st.utdup time nury bc e�perienceJ durim_ consvuction in thc <br /> ;it� suils. Tlic lill soils were observcd tu bc loose to medium dense and as result, may have shorter sr.md <br /> I up timc. Cleaner sand and eracel soils ur suils IocateJ in areas �vidi perched �_ruundwater may also <br /> exhibit shorter ,tandup time,. Sp:illing anJ raveling uf the cut face may occur at these locatiuns durin_ <br /> soil nvil ��:�II instullatiun Constructiun �eclutiques used to miti�_ate spallin, and r.rvalinc include: <br /> � . I�lush co:iting the cut face «'ith 3 to a inchcs of �homrete immediatel}� after the cut face is <br /> � e�caeated ro final line and Ute drainaee m;uerial is iiutc�lled. This qpically provides enuu�=h <br /> ir,indup time tu ;�Iluw tix the in;tallatiun of the rcinturcin� steel and tinal shotcrcte. <br /> � I:xr,ic;uing in hall�hcicht (�- to 3-luut) li�is, �uth�r than tiill heieht (G-foo[) li(is. <br /> . <br /> I <br /> . I:�cav.um�, Ica�inc a I Ii:I V �;�rth berm in Gont of the walL The soil nails �re insutlled by <br /> drillina throuah thc soil bu'm. The soil berm is then removed to alluw for installution ot die <br /> �, draina�c nuueriol m�d reinfortine steel and shotcrom. <br /> . Shurtenine the lengdi of��:ill drilled :nd shutcrc�eJ usim� a st.r,gered ezcavatiun approach. <br /> I <br /> � P11{C�y GEOENGINEEflS� <br /> cilrAir l�l'i�-�iu��ui <br /> � ,Iw;u,l1�9. :pUG <br />