Laserfiche WebLink
C. Cutoff Trench <br /> The cutoff trench shall extend at least 3' below the foundation surface measured after the <br /> weathered or top 2' of bedrock is removed. <br /> Where claystone is encountered: <br /> After excavation the trench shall be watered,rolled and compacted to provide a suitable <br /> bonding surface for the first lift of embankment soil. Claystone foundation shall be <br /> covered with slope liner fill soon after preparation to prevent drying and desiccation of <br /> bedrock foundation. <br /> Where excavations met with refusal(e.g. Sandstone material): <br /> The cutoff trench shall cleaned with a blade(such as a dozer blade). The bottom and <br /> sides of the cutoff trench shall be suitably cleaned before embankment soil placement. <br /> The Design Engineer or representative of the Design Engineer shall make the final determination <br /> the method of foundation or cutoff trench bottom preparation. <br /> 3.03 STRIPPING <br /> The entire area to be occupied by the embankment shall be stripped to a sufficient depth,as determined by <br /> the Design Engineer,to remove all unsuitable materials. The unsuitable materials to be removed by <br /> stripping shall include all surface boulders and loose rock,debris,topsoil,vegetable matter,including <br /> stumps and roots,and all other perishable and objectionable materials that are unsuitable for use in <br /> permanent construction required under these Specifications or that might interfere with the proper bonding <br /> of the embankment with the foundation or the proper compaction of the materials in the embankment,or <br /> that may be otherwise objectionable as determined by the Design Engineer. <br /> 3.04 PLACING CUTOFF TRENCH AND EMBANKMENT MATERIALS <br /> The suitability of each part of the foundation for placing embankment materials thereon,and of all <br /> materials for use in embankment construction,will be determined and approved by the Design Engineer. <br /> No embankment material shall be placed in the embankment when either the material or the foundation or <br /> embankment on which it would be placed is frozen. <br /> In any separate portion of cutoff trench or embankment being constructed,each layer of each zone shall be <br /> constructed continuously and approximately horizontal for the width and length of such portion at the <br /> elevation of the layer. If transverse slopes are required in the cutoff trench or embankment,slopes shall be <br /> no steeper than 4:1 (horizontal to vertical). <br /> The Contractor shall maintain the cutoff trench and embankment in an approved manner,including <br /> maintaining working surfaces free of weeds and other organic matter until final completion and acceptance <br /> of all the work under the contract. <br /> If,in the opinion of the Design Engineer,the surface of the prepared foundation or the compacted surface <br /> of any layer of earthfill is too dry or smooth to bond properly with the layer of material to be placed <br /> thereon,it shall be moistened and/or worked with harrow, scarifier,disc,or other suitable equipment,in an <br /> approved manner to a sufficient depth to provide a satisfactory bonding surface before the next succeeding <br /> layer of earthfill material is placed. If in the opinion of the Design Engineer,the compacted surface of any <br /> layer of the earthfill in-place is too wet for proper compaction of the layer of earthfill material to be placed <br /> thereon,it shall be removed,allowed to dry;or be worked with harrow,scarifier,disc,or other suitable <br /> equipment to reduce the moisture content to the required amount;and then it shall be recompacted before <br /> the next succeeding layer of earthfill material is placed. <br /> Section 02290-Page 4 of 6 6/10 <br />