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1 � <br /> . � � CIVILDESIGN <br /> ��o�o copY <br /> November 12, 2011 ry.-�,�`�d �,�� <br /> JI� <br /> William Koch � S�u,�N� �LC(��� <br /> 3251 Casco Circle �v + �� _J <br /> Orono, MN 55391 �(,(,l.Vl �i✓t������ <br /> �t� n .�-�,��L���� <br /> Re: Slope Stability Analysis <br /> 3251 Casco Circle �� <br /> Orono, MN <br /> Dear Mr. Koch <br /> As requested, Civil Design Professionals (CDP) has conducted a professional slope stability analysis <br /> of proposed modified slope at 3251 Casco Circle, in Orono, MN. The purpose of the investigation <br /> was to determine the long-term stability of both the proposed slope with the new retaining wall <br /> system and fill cover and the proposed slope with fill burying the existing retaining wall system. In <br /> addition, CDP was asked to evaluate the Slope Stability Analysis Report previously conducted on <br /> the slope by Gray Engineering, LLC for accuracy. <br /> CDP was provided the following information for use in our analysis (attached): <br /> • William Koch Documents submitted the City of Orono <br /> 1. Existing Lot Survey by Advanced Surveying and Engineering Co. dated July 1, 2011 <br /> 2. Hennepin County Property Tax Map—Tax Year 2011 <br /> 3. Sub-Terrainian Wall System Section—Concept Landscaping <br /> 4. Stair System Plan—Concept Landscaping <br /> 5. Stair System Elevation and Typical Section—Concept Landscaping <br /> 6. Planting Plan—Concept Landscaping <br /> 7. Sub-Terrainian Walls Buried (Replace Rotten Timber Walls) —Concept Landscaping <br /> • Grading Plan—Otto and Associates, dated 9/7/11 <br /> • Gray Engineering, LLC Slope Stability Analysis Report, dated August 4, 2011 <br /> � Gray Engineering, LLC Slope Stability Output <br /> CDP performed a site visit on Monday October 24, 2011, to meet with Independent Testing <br /> Technologies to identify soil boring locations. Soil borings were subsequently drilled on Tuesday <br /> October 25, 2011. The borings were required to determine the actual soil strata at the slope as well <br /> as to retain in-situ soil samples, which were later tested for peak shear and cohesive strength. <br /> Global stability analysis is highly sensitive to assumed soil strength values, therefore obtaining soil <br /> strength data is critical on steep slope applications such as the slope on your property. The borings <br /> were drilled on either side of the lot near the top of the slope to provide the best representation of <br /> the existing slope strata using only two borings. <br /> Please find attached the following information which was obtained from the soil borings and used to <br /> assess the long-term stability of the proposed slope: <br /> Civil Design Professionals • 8609 Lyndale Ave. S., Suite 200 Bloomington, MN 55420 • Office 952-303-5312 • www.cdp-us.com <br /> 1 <br />