A. Monitoring: All phases of rockery-wall construction shall be monitored by the geotechnical engineer employed by the owner/contractor to verify that the nature and quality of the materials being used are appropriate and that the construction is in accordance with the engineered design. The geotechnical engineer shall verify to the city in writing that the materials and construction of the rockery wall as-built is in accordance with the engineered design after construction is complete.

B. Fill Compaction: Where the rockery walls are constructed in front of a fill, the fill shall be placed and compacted in a manner that will provide a competent fill mass as noted in the drawings. All fills shall consist of quality fill meeting the geotechnical engineer’s recommendations as noted on the drawings or report.

C. Compaction Testing: Density tests to verify compaction shall be taken at random locations. At least two (2) tests per one hundred feet (100') of wall length per two feet (2') of backfill shall be taken. In critical locations, the geotechnical engineer may request additional monitoring. The testing shall be conducted by a certified technician under the direction of the geotechnical engineer.

D. Fill Construction Reinforcement: All fill placed behind rockery walls shall be reinforced as recommended by the geotechnical engineer.

E. Rock Selection: The contractor shall have sufficient space and stockpile material available to select from among a number of rocks for each space in the rockery wall to be filled. Rock should be of a generally cubical, tabular or rectangular shape. Rounded rocks should not be used and internal void spaces in the facing should be kept to a minimum. Prior to being placed, all rock shall be inspected and approved by the geotechnical engineer. The rock source shall be preapproved by the geotechnical engineer. Rocks shall be placed to decrease in size with increasing wall height. Rocks shall be placed to bear on good flat-to-flat surfaces. The long dimension of the rocks shall extend back toward the cut/fill face. Rocks shall bear on at least two (2) or more other rocks.

F. Rock Placement: Rock shall be placed as recommended by the geotechnical engineer. A keyway (one-foot (1') minimum) as recommended by the geotechnical engineer shall be constructed into unyielding soil.

G. Drainage: A rock drainage filter or geosynthetic filter fabric shall be installed between the rear face of the rock wall and soil face being protected. The drainage design shall consider adjacent conditions and potential for water and erosion and shall be constructed as directed by the engineer.

H. Surface Drainage: Surface drainage shall be directed away from the rockery-wall face to a positive and permanent discharge well away and beyond the rock wall. The surrounding site shall be graded such that water cannot flow over the top of the wall.

I. Steepness of Walls: The steepness of the wall shall not exceed one horizontal to six vertical (1:6). Specific recommendations from the engineer are required and shall be noted on the drawings.

J. Slopes: Slopes above and below walls shall not exceed two horizontal to one vertical (2:1). (Ord. 2019-10-002, 10-10-2019)