3007 PANAVIEW BLVD 2016-01-01 MF Import

$eptember 2,1997 5 973-1164100 5.2 Remedial Recommendationa - 5.2.1 General We discussed with you your desires mgarding how you would like your yard to look _ and what facilities you would like to re-construct as part of the remediation of the slide. After diecwsions with you about re]ative cosb and feasibility of different options and what they muld allow you to do with your yard,we understand that your paramount - rnncem is that the failure not propagate up the slope and threaten your house. In addition,you did not want to re-establish the original ground surface gcades,however, you may,in the future,want to have the ability to mnstruct a deck out over the ama of � the slump failure, Our rnmediation remminendations were made with this criteria in mutd. We also understand ttiat the mnstruction is intended to be rnmpleted this summer and fall prior to the onset of the winter rains. Sahuation of the fill mass was the principal cause of the fill failure. Therefore, establishing impmved drainage in the fill block that slumped will improve long-term - stability. In addition to drainage measures,we mnsidered and rejected several possible remediation options primarily for cost and access reasons. These included the followin� - . construction of soldier-pile retaining wall or cast-in-place concrete wall, • mnstruction of a reticulated tnicro-pile wall, • over-excavation and replacement of the poor quality fill involved in the failure, � �,y}a]�g��¢r drains perpendicular to the slope, . and applying soil admixtures such as cement to improve the strength qualifies of the existing fill, You should understand that no mmediation option can guarantee that no futvre movement will occur on the slope. More robust systems such as structural retaining walls provide the greatest factor of safety against future movement while drainage options typically offer a sonuwhat lower factor of safety. In our judgment,the • prnferred option described below will provide the most reasonable cosWenefit mnsidering the difficult site access mnstrainls. - 5.2.2 Preferred Remediation Alternative In general,this altemative will include installation of a deep French drain in the upper - portion of the slumped arna of the slope along with the application of some soil cement admixing of the fill to improve stability and provide foundation bearing for future deck supports if needed. A sketch illustrating these recommendations is shown on Figure 5. It shows the approximate location for the excavation of a deep trench on the level bench of the - slumped block of fill. The trench depth will likely be about 12 to 14 feet deep and a minimum of three feet wide and be graded to drain by gravity down to the north dolder Auoefates