3007 PANAVIEW BLVD 2016-01-01 MF Import

September 2,1997 6 973-1164.100 � toward the Frishman rnsidence. The intent is to excavate the trench about tluee feet into the native till soils below the fill so the actual depth will have to be field verified. in •-- general,the trench should be located toward the downslope edge of the bench. This will rnduce the risk of possible trench caving causing additional movement in the fill adjacent to the hovse. The lower three feet of the trench will be backfilled with a marse — angular rock free of finea auch as railroad ballast to Provide a drainage layer. The top of the rocic should be rnvernd with a filter fabric to help prevent clogging and mntamination from the trench backfill. In addition,strips of a mmposite drainage fabric ~ auch ae Miradrain or Incadrain should be p]aced against the upslope side of the trench at regiilar intervals(about every twelve feet)with the bottom of the atrips terminating in the drainege rraveL The top af the drainage fabric should stop about a foot from the •— grovnd surface so it dces not mllect surface water. The remainder of the trench can be backfilled with the native fill material. Since the fill '— was observed to be wet and loose in our explorafions,we remmmend that it be improved by admixing it with powdemd cement prior to placing and mmpacting it back inM the trench. We intend to use the area of the hench backfill as a future location for deck poat footings. In addition the soil admixing will ptovide an added measure of , stability due to the added strength of the soil. We remmmend a mixing ratio of about thiee percent powdernd cement. Assuming a wet soil unit weight of about 100 pcf that -' would require mixing about 80 pounds of cement for each cubic yard of soil backfill. , The cement treated backfill should be placed in the trench in maximum one foot thick lifls and compacted usingeither a vibratory plate compactor such as a hoe-pac or a ' sheepsfootmlleratfachment. The north end of the trench should be day-lighted onto the slope failure on the ' Frishman property. A tightline pipe should be placed in the end of gravel drain and extend down the slope to the creek The pipe installation should be coordinated with the repaus to the Frishman slope so that the mntractor will not have to re�xcavate the rock on the Frishman slope to place the drain pipe for your drain We understand that the same mntractor will be used for repairs to both your slope and the Frishmans and that you will be working cooperatively on the repairs. . 5.2.3 AddiHonal Recommenda8one In addition to the mmediation options described above,we remmmend that the _. rnntractor locate all roof gutter downspout,footing dcain lines and yard drains that daylight on the downslope side of the house. Each drain should be inspected for leaks, rnpaired if necessary and mnnected to tightlines that terminate in the creek at the toe of . . the slope. The steep face of the scarp formed by the slump should be protected from long-term . erosion damage usingsome form of landscaping block wall,rockery,or wood lagged pile wall. The facing should be backfilleo with a free draining sand and gravel and a four-inch-diameter perforated drain pipe should be installed behind the base of the �-. wall. The drain should be mnnected by a tightline pipe that empties into the creek ��. �4 Golder Assoelates