There is a quarry out in Contra Costa County where the huge boulders for the rehabilitation of the creek bed were obtained. The individual boulders weigh in at 4,000 lbs., with smaller ones tipping scales at between 1,200 and 1,800 lbs. They have to weigh this much or the force of the waters flowing through the culvert at high rainfalls would wash them away, literally! Here they are being delivered by dump truck - thick plywood sheets were laid down on the lawn area to protect it while it receives the multiple loads of boulders. As they were unloaded, they caused the earth to shake, and the house with it...
Initially the excavator operator placed huge boulders along the eastern bank of the creek to shore it up - he then carved out a downslope toward the creek to serve as a platform from which he would then not only place boulders in designated locations in the creek bed, but also sculpt the hillside to ultimately receive the retaining wall - the operator showed consummate skills in manipulating those boulders, and sculpting the hillside... |
The law of the universe struck once again, when the excavator's auger struck rock in two of the four pier holes...! This required bringing in special jackhammers and drills to get through the layer of rock. Each pier hole had to be 16 feet deep - because of the subterranean rocks, this took some doing. Then, once the auger was through the rocks and it reached a depth of 12 feet, it hit the water table, and each hole filled with water. This turned the soil which usually clings to the auger bit as it is drawn up and out of the hole, into mud and slush, dripping off the bit and preventing the soil from being withdrawn from the holes. Additionally, the water prevented eye-balling how the work was proceeding. This then required that a special mud/slush sucking machine, a super shop-vac mud sucker be brought in - so, yet another delay...
Once the piers were dug properly, the excavator was used to lift and install the large and heavy H-beams into place - an engineer named Dove from the design firm came to supervise the installation... |
