Loading...
HomeMy WebLinkAboutTract Map 32437-1 SupplementalGeotechRecs(Mar.27,2006), • ~ 1 ~~~ Leighton and Associates, Inc. A LEIGHTON GROUt' COMPANY Mazch 27, 2006 To: Lennar Communities Inland Division 391 N. Main Street, Suite 301 Corona, Califomia 92880 Attention: Mr. Kevin Lynch ~ Project No. 110231-061 Subject: Supplemental Geotechnical Recommendations, Subgrade Compaction for In Tract Streets, Tract 32436-1, -F, 32437-1, -2, -3, and -F, Harveston Communities, City of Temecula, Riverside County, California In accordance with your request, Leighton and Associates, Inc. (Leighton) has prepared the following supplemental geotechnical recommendations for yielding (pumping) subgrade conditions on the streets within the subject Tracts. Due to the recent seasonal rains, yielding subgrade conditions were encountered within the street sections. Leighton has been providing recommendations to remediate the yielding subgrade conditions on a case by case basis. This letter provides general recommendations that can be utilized to remediate street subgrade yielding conditions due to excessive moisture. • Minor to Moderate Yieldin ~ Sub r~ade_: Subgrade exhibiting minor to moderate pumping may be remediated by excavating 6 inches below the design subgrade, placing a layer of stabilization fabric (Mirafi HP570 or equivalent) over the affected area, and placing Class 2 aggregate to the design base grade. • Moderate to Severe Yielding Subgrade - Subgrade exhibiting moderate to severe pumping may be remediated by excavating 12 inches below design subgade or near the top of existing utilities (contractor to determine safe depth). After removal of wet materials, a 5 to 6-inch layer of 3-inch (maximum size) crushed rock should be placed in the excavation area. The rock should then be worked with heavy vibratory compaction equipment to push the rock into the underlying soils. If yielding conditions persist following the rock placement, additional crushed rock or a layer of stabilization fabric (Mirafi HP570 or equivalent) should be placed over the affected azea. The fabric should extend a distance of at least 5 feet beyond the affected area. Compacted Class 2 aggregate base should be placed over the fabric or stabilized azea to the design elevation. ~ 41715 Enterprise Circle N., Suite 103 ^ Temecula, CA 92590-5661 951.296.0530 ^ Fax 951.296.0534. www.leightongeo.com • ~ 110231-061 March 27, 2006 The remedial grading, placement of stabilization fabric, and compaction of replacement materials should be observed and/or tested by Leighton. The results of either remedial method may vary and it is the contractor's responsibility to achieve the non-yielding compacted subgrade prior to aggregate base placement. Additional recommendations may be provided in the field on the basis of actual conditions encountered. If you have any questions regarding this report, please do not hesitate to contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ~ Arasan Sing yah Project Engineer Distribution: (1) Addressee (3) Job Site, Attention: Mr. Mazk Young ~ ~ -2- Leighton