Page 6 - Minutes of Proceedings of Civil Engineers Vol CXCV 1913-14 Part 1

46 wENTwoRTH-SHEILDS oN THE coNsrRUcrIoN oF . fMinutes of tongued whole-timber shoet-piling was driven parallel to the bank and immediately to the north of it (Fig. a). In spite of these precautions, a large quantity of water found its way in-nearly a rnillion gallons per diem :rt one time. Part of this water came in through openings in the sheet-piling, and a larger part through the gravel bed underneath the bank, which, though porous, was too hard to be penetrated by the piles. This soakage-water was all led to special sumps by a system of grips and drains, and ofi'ered no peculiar difrculties, though the cost of pumping it was consider.able. Top Ex,cauati,on area of the dock thus enclosed was ercavated -The all over to a depth of 30 feet below quay-level by steam-navvies and hand-labour gangs. The spoil was disposed of in two ways. The smaller portion (about 111,000 cubic yards) was hauled up an incline in tip wagons, and then conveyed for about a mile to reclaim some nrudlands belongiug to the Southampton Corporation. The larger portion (about 595,000 cubic yards) was tipped into hoppers and sent to sea, as no use could be found for it, In order to effect this, the tip wagons were drawn up another incline on to a high-level stage built out over the river (Fig. ). From this stage the contents of the wagons were discharged down shoots into steam hopper-barges, which took the material to the tipping-grounds east or west of the fsle of 'Wight, a distance of about 25 miles. Five hoppers were used for this purpose and were able to dispose of about 12,000 cubic yards per week. Trench Eacauation,-As soon as the excavation had been carried down in this fashion to about 30 feet below quay-level, heavily timbered trenchos were sunk, in which to build the deep quay-walls. These trenches were about 43 feet wide at the top, diminishing to 39 feet at foundation-level, and about 43 feet deep. The arrange- ment of the timbering is shown in the cross section, Fig. 5, Plate 1. The trenches were drained in the usual way by pipes laid along the back, and leading to a special deep-level sump sunk in the dumpling, or to small independerrt sumps formed in the trench itself, the latter sumps boing eventually filled with concrete. Concrete Materials.-The cement was all made to comply with the British Standard specification. The aggregate was flint gravel dredged from Langston Ilarbour, near Portsmouth. It was very clean and contained a varying proportion of coarse sand, For mass and block work the gravel was used as it came from the dredger, except that often a proportion (not exceeding l0 per cent.) of fine sond was ndded, which seemed to improve its consistency. The volumetric analysis of two specimens of gravel, one with and the othor without the added fine sand, is shown in Fig.6 @, a7).