t Experimental data for the foroe distribution on three model oylind-rioal piles for three nave conditions.are presented. These results are compared to the previously published theory.**' Introduetiom The purpoao of this report is to present experimental data on the foroe distribution exerted by surfaoe waves on piles* From these data the ooeffioients of drag and mass that appear in the equation**' for the foroe were obtained* The experimental results were compared to the calculated foroe distribution* In order to simplify the presentation, the foroe (lbs) was divided by the projected area (ft 2) of a segment of the pile to give a foroe intensity (lbe/ft 2). The measurement of foroe was made on a one-inoh'high segment of several model piles of various diameters* The results of these studies are that the experimentally determined coefficient of mass shows good agreement with the theoretical value of 2*oC 7 » 8), and relatively good agreement with the values in previously presented experiments(1#2,3,4,5,467. The results also show that the experimentally determined ooeffioient of drag is in relatively good agreement with the value 1*6 as found in previous experiments(^» 2 » 5 »*»* 6 '' The measurements of the foroe intensity distribution showed good agreement with the oaloulated distribution using the previously mentioned values of the ooeffioi-ents in the equation for the foroe*
Studies of interstitial waters obtained from DSDP Leg 64 drill sites in the Gulf of California have revealed information both on early diagenetic processes in the sediments resulting from the breakdown of organic matter and on hydrothermal interactions between sediments and hot doleritic sill intrusions into the sediments.In all the sites drilled sulfate reduction occurred as a result of rapid sediment accumulation rates and of relatively high organic carbon contents; in most sites methane production occurred after sulfate depletion. Associated with this methane production are high values of alkalinity and high concentrations of dissolved ammonia, which causes ion exchange processes with the solid phases leading to intermediate maxima in Mg + + , K + , Rb + , and Sr + + (?). Though this phenomenon is common in Leg 64 drill sites, these concentration reversals had been noticed previously only in Site 262 (Timor Trough) and Site 440 (Japan Trench).Penetrating, hot dolerite sills have led to substantial hydrothermal alteration in sediments at sites drilled in the Guaymas Basin. Site 477 is an active hydrothermal system in which the pore-water chemistry typically shows depletions in sulfate and magnesium and large increases in lithium, potassium, rubidium, calcium, strontium, and chloride. Strontium isotope data also indicate large contributions of volcanic matter and basalt to the pore-water strontium concentrations. At Sites 478 and 481 dolerite sill intrusions have cooled to ambient temperatures but interstitial water concentrations of Li + , Rb + , Sr + + , and Cl~ show the gradual decay of a hydrothermal signal that must have been similar to the interstitial water chemistry at Site 477 at the time of sill intrusion. Studies of oxygen isotopes of the interstitial waters at Site 481 indicate positive values of δ 18 θ (SMOW) as a result of high-temperature alteration reactions occurring in the sills and the surrounding sediments.A minimum in dissolved chloride at about 100-125 meters sub-bottom at Sites 478, 481, and particularly Site 479 records a possible paleosalinity signal, associated with an event that substantially lowered salinities in the inner parts of the Gulf of California during Quaternary time.
Problems pertaining to the transportation of sediment by flowing water have been extensively studied by engineers and scientists during the last few years. Most of the various experiments have been concerned with either bed‐load or suspended load, but seldom have they been studied simultaneously. When bed‐load and suspended load occur simultaneously in a flume or stream a distinct difference in their mechanical composition is often observed. A curve fitted to the plotted data from a mechanical analysis of the bed‐material shows a distinct break. This break occurs most commonly in the data plotted from samples taken in mountain streams where the bed‐material is extremely coarse. For instance, in the Rhine River, Switzerland [see 5 of “References” at end of paper] the bed‐material ranges in size from pebbles 5 mm in diameter to boulders 100 mm in diameter and greater. Between boulders and in protected pools, however, sand one mm in diameter and finer is found, whereas particles ranging in size from one to five mm are not present. The explanation for this size‐distribution has been that the material greater than five mm in diameter moves as bed‐load and the material finer than one mm in diameter moves as suspended load. Particles ranging in size from one ram to five mm in diameter occur rarely for certain geologic or hydraulic reasons [3].
A summary of the various instances where wave theories have been verified experimentally is presented briefly. A more detailed discussion is given for those problems where models built to several scales have permitted an evaluation of the effect of scale in the application of data from hydraulic models.
The results of an experimental investigation on the damping action of submerged rectangular breakwaters are presented. The experimental data also are compared with published theories. A new theory is presented which compares more favorably with the experiments than the previous theories. Also given is a summary of all available published theoretical and experimental information on the damping action of trapezoidal and triangular breakwaters, reefs of various configurations, and plane barriers of various orientations.
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