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HomeMy WebLinkAboutCT 83-15; CAMINO POINTE; REPAIRING AND REPLANTING SLOPES; 1984-07-23Project No. 59331A-ECO1 S FORSUM/SUMMERS & PARTNERS, INC 34118 COAST HIGHWAY, DANA POINT, CALIFORNIA 92629 (714)4%.6111 LANDSCAPE ARCHITECTS, ASLA ' July 23, 1984 CAMINO POINTE Carlsbad, Calif. Tract 79-27 PROCEDURES FOR REPAIRING AND REPLANTING SLOPES STEEPER THAN 2:1 - INTRODUCTION It has been observed that certain areas on the °prdject slopes that are steeper than 2:1 are showing signs of creep (soil displacement). The following information outlines the procedure for repairing these areas to a level of acceptable structural stability. In addition, the repair of certain areas adjacent to the existing terraces and brow ditches will be addressed. OUTLINE OF PROCEDURES I. Clearing and Grubbing of Slopes A. All surface vegetation shall be stripped off by hand and removed from the designated areas on the slopes. 'II. Soil Removal From Slope '• - - ' evaluated SurTace soil shall be removed to the depth de-tc-rmined- by the Soils Engineer in the field. , - Soil shall be stockpiled along the terrace and brow ditches for later use. Once soil has been removed, Soils Engineer shall inspect the slope to 4eterminc- structural stability. evaluate III. Reconstruction of Slope (Backfilling) A. Soils Engineer shall recommend a suitable backfill material that shall be üsed:i1th the existing soil previously removed from the 'slope. Project No. 59331A-ECO1 ,' •., B. Backfill materiwill be'put,.back on the slope 10611 lifts. S Material will be placed and carefully compacted with - pneumatic equipment and watered to achieve 90 percent - compaction rating D. Soils Engineer shall test the backfill 'compaction at ' -e,very2'-3' vertical intervals to iu-ro--90% compaction. : E. Upon completion of slope reconstruction, Engineer shall make observation and inpcct and appravc ior4-.express an opinion relative to contractors, adheranceto plans and specifications.' IV Replanting of Slope In order to assure the fastest re-vegetation of the- - repaired slope as possible, it is recommended to hand plant, at twelve inches (12") o.c. a liner size plant material and a nurse crop of hand seeded Alyssum "Royal Carpet" only. 'The hand seeded Alyssum will insure immediate-stabilization of the surface soil while the liners are growing to provide a permanent surface covering. '• The liners shall be Grindelia' Stricta (Prostrate Gum Plant).' It is a native ground 'cover that is a re-rooting, 'deep rooting,' low water requiring perennial. Once it is established, generally within' six (6) months, the water may be shut off, with 'an occasional watering during the hot summer months. City shall 'approve plant suggestion prior to installation. V. 'Repair of Terrace and Brow Ditches S • replacing and This shall consis Fecompacting soil that has begun-4e errode4along the edges of the concrete-ditches.- • ' Soil backfill shall be hand placed and compacted with - pneumatic equipment and repaired to its original condition in accordance with earthwork specifications; VII. Maintenance of Repaired Slopes The repaired slopes shall have two (2) types of maintenance procedures.' These will address,the immediate period (90)- days and the long term period (Continual). Project No. 59331AEcO ia Immediate Maintenance Period (Installation) Watering -...Contractor shall determine the proper watering ,• inconsi'stant schedule for germination of hydroseed material ' with paragraph based on the type of soil, time of year, and IV-A hydroseed requirements. Soil surface must be kept moist at all times' during germination period to avoid desication of seedlings. However, 'no runoff of water from the slopes shall be allowed. Caring of Slopes - Slope areas shall be kept undisturbed of any foot traffic for a minimum of (60) days or as directed by Landscape Architect. Guarantee - Contractor shall re-seed any slope areas that fail to germinate evenly and repair all eroded surfaces. Inspections -'Contractor shall be expected to-make a minimum of (1) 'weekly visit during 90 day maintenance period. Contractor shall request a Final inspection from the Landscape Architect (7) days prior to end of maintenance period. Upon acceptance of project, Contractor shall be 'relieved of any further maintenance obligations. Long Term Maintenance Period (Continual) - Upon acceptance of project, a qualified maintenance company shall be responsible for the following: Watering - Once proper germination of hydroseeded areas have taken place, a watering schedule will be established on a seasonal basis taking into consideration the watering requirements of the plant material. No runoff of water should be allowed. Fertilizing - Slope shall be fertilized every 90 days with a balanced fertilizer determined by Soils reports. - - ' Weeding -,Selective herbicides applied per manufacturers recom- mendations shall be used whenever possible to keep all slopes weed free. Trash & Debris-All slope'areas, terrace and brow ditches, drains, etc, are to be kept free of trash and debris. 'Maintenance company shall have on hand sufficient manpower to assure proper maintenance procedures. Limitations - It 'is,understood that 1½ to 1 slopes are inherintly susceplable to shallOw sloughing. Periodic rebuild- ing of the slopes, may be required. Periodic mainten- ance should be done in accordance with sections I through III above. Project No. 59331A-11 S GUIDE SPECIFICATIONS FOR CONTROLLED FILL GENERAL These specifications cover preparation of existing surfaces to receive fills, the type of soil suitable for use in fills, the control of compaction, and the methods of testing compacted fills. It shall be the contractor's responsi- bility to place, spread, water and compact the fill in strict accordance with these specifications. A soil engineer shall be the owner's representative to observe the construction of fills. Excavation and the placing of fill shall be -under the direct observation of the soil engineer, and he shall give written notice of conformance with the specifications upon completion of grading. Deviations from these specifications will be permitted only upon written authorization from the soil engineer. A soil investigation has been made for this project; any recommendations made in the report of the soil investigation or subsequent reports shall become an addendum to these specifications. SCOPE The placement of controlled fill by the contractor shall include all clearing and grubbing, removal of existing unsatisfactory material, preparation of the areas to be filled, spreading and compaction of fill in the areas to be filled, and all other work necessary to complete the grading of the filled areas. MATERIALS Materials for compacted fill shall consist of any material imported or excavated from the cut areas that, in the opinion of the soil engineer, is suitable for use in constructing fills. The material shall contain no rocks or hard lumps greater than 24 inches in size and shall contain at least 40% of material smaller than I inch in size. (Materials -greater than 6 inches in size shall be placed by the contractor so that they are surrounded by compacted fines; no nesting of rocks shall be permitted.) No material of a perishable, spongy, or otherwise improper nature shall be used in fills. Material placed within 24 inches of rough grade shall be select material that contains no rocks orhardlumps greater than 6 inches in size and that swells less than 3% when compacted as hereinafter specified for compacted fill and soaked under an axial pressure of 160 psf. Representative samples of material to be used for fill shall be tested in the laboratory by the soil engineer in order to determine the maximum density, optimum moisture content, and classification of the soil. In Project No. 59331A-ECO1 I addition, the soil engineer shall, determine the 'approximate bearing value of a recompacted, saturated sample by direct shear tests or other tests applicable to the particular soils. 4. During grading operations, soil types other than those analyzed in the report of the soil investigation may be encountered by the contractor. The soil engineer shall be consulted to determine the suitability of these soils. IV. COMPACTED FILLS 1. General Unless otherwise specified, fill material shall be compacted by the contractor while at a moisture content near the, optimum moisture content and to a density that is not less than 90% of the maximum dry density determined in accordance with ASTM Test No. D1557-78, or other density test methods that will obtain equivalent results. Potentially expansive soils may be used in fills below a depth 'of 24 inches 'and shall be compacted at a moisture content greater than the .optimum moisture content for the material. 2 Clearing and Preparing Areas to be Filled All trees,, brush, grass, and other objectional material shall be collected, piled, and burned or otherwise disposed of by the 'contractor so as to leave the areas that have been cleared with a neat and finished: appearance free from unsightly debris. All vegetable matter and objectionable material shall be removed by the contractor from the 'surface upon which the fill is to be placed, and any loose or porous soils shall be removed or compacted to the depth shown on the plans. The surface shall then be plowed or scarified to a minimum depth of 6 inches until the surface' is free from uneven features that would 'tend to prevent uniform compaction by the equip- mentto be used. Where fills are constructed on hillsides or 'slopes, the slope of the original ground on which the fill is to be placed shall be stepped or keyed by the contractor as 'shown on the figure included in these specifications.' The; steps shall extend completely through the soil mantle and into the, underlying. formational materials. (ci) After the foundation for the fill has been cleared, plowed or scarified, it shall be disced or bladed by the contractor until it is uniform and free from large clods, brought to the proper moisture content, and compacted as specified for fill. , ' 'Project No. 59331A-,1 3. Placing, Spreading, and Compaction of Fill Material The fill material shall be placed by the contractor in layers that, when compacted, shall not exceed 6 inches. Each layer shall be spread evenly and shall be thoroughly mixed during the spreading to obtain uniformity of material in each layer. When the moisture content of the fill material is below that specified by the soil engineer, water shall be added by the contractor until the moisture content is as specified. When the moisture content of the fill material is above that specified by the soil engineer, the fill material shall be aerated by the con- tractor by blading, mixing, or other satisfactory methods until the moisture content is as specified. After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted by the contractor to the specified density. Compaction shall be accomplished by sheepsfoot rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of acceptable grading equipment. Equipment shall be of such a design that it will be able to compact the fill to the specified density. Compaction shall be continuous over the entire area, and the equip- ment shall make sufficient trips so that the desired density has been obtained throughout the entire fill. The surface of fill slopes shall be compacted and there shall be no excess loose soil on the slopes. V. INSPECTION Observation and compaction tests shall be made by the soil engineer during the filling and compacting operations so that he can state his opinion that the fill was constructed in accordance with the specifications. The soil engineer shall make field density tests in accordance with ASTM Test No. D1556-64. Density tests shall be made in the compacted materials below 'the surface where the surface is disturbed. When 'these tests indicate that the density of any layer of fill or portion thereof is below the specified density, the particular layer or portion shall be reworked until the specified 'density has been obtained. VI. PROTECTION OF WORK 1. During construction the contractor shall properly grade all excavated surfaces to provide positive drainage 'and prevent ponding of water. He shall control surface water to avoid damage to 'adjoining properties or to finished work on the site. The contractor shall take remedial measures to prevent erosion of freshly graded 'areas and until such time as permanent drainage and erosion control features have been installed. :. Project No. 59331A-11 2. After completion of grading and when the soil engineer has finished his observation of the work, no further excavation or filling shall be done except under the observation of the soil engineer. - Strip as specified / original ground / N Slope ratio N • M Fill Slope to be such that .sloughing or sliding does. - not occur • Remove all topsoil Varies1 See note See note NOTES: The outside edge of bottom key "A" shall be below topsoil or loose surface material. • The minimum width of "B" Bench shall be 2 feet wider than the compaction equipment, and not less than 10 feet. Keys are required where the natural slope is steeper than 6 horizontal to 1 vertical, or where specified by the soil. engineer.