As a rigid object is pushed into a soil, acoustic emissions are generated by soil grains sliding over one another, sliding over the penetrating object, and being crushed. In 1977, a research project was initiated to develop a system for recording such emissions generated during the quasi-static cone penetration of soils, and to evaluate their potential usefulness as a means for the in situ characterization of soils and soil deposits. In order to ensure knowledge of and control over all factors governing the engineering behavior of tested soils, all initial tests were performed in the laboratory. A field testing program has recently been initiated. Laboratory tests to date have been performed on a single graded sand. Variables included relative density, confining stress, and state of saturation. Analyses of the obtained acoustic records include the determination of peak-to-peak voltage, root-mean-square voltage, and frequency distribution analysis. Initial results indicate that: 1. The resultant frequency distribution curves can be divided into two categories, one associated with lower confining stresses and penetration rates, the other with higher confining stresses and penetration rates, the other with higher confining stresses and penetration rates. These categories may well be signatures uniquely associated with the specific soil. 2. The amplitude of the signal increases with penetration rate. 3. The amplitude of the generated signal is larger in a dry, than in a saturated sample. The limited field tests performed to data indicate that amplitude of the generated signal may be used as an indicator of layering. The goal of the ongoing project is the development of a new method for the in situ identification and characterization of soils and soil deposits.

No abstract

A series of consolidated undrained static and cyclic simple shear tests was conducted on highly overconsolidated silt from offshore California. The observed behavior indicates a tendency for initial contraction followed by dilation.As a result, the total stress path followed by in-situ soils has to be carefully considered in evaluating their performance under foundation loads.----~--

Under the Pacific Ocean off the south coast of Peru the Nazca tectonic plate subducts beneath the South American plate, creating a high seismic hazard along this coast. Onshore site development and preparation for LNG plant and export terminal construction in this area required a significant volume of excavation throughout the process area and storage area, which are located on a plateau cut to elevation 125 m, separated from the marine loading terminal by coastal cliffs. Steep cuts were incised into the plateau to build a 3.5H:1V sleeper way to allow the LNG cryogenic pipeline system to traverse down the cliff onto a marine jetty to reach the loading terminal. Approximately 230 thousand cubic meters of spoils resulting from the excavation of the sleeper way were pushed over the cliff onto the undercliff area. Additionally, about 630 thousand cubic meters of the stripped material from the process and tank area was pushed over the cliff onto existing colluvial materials in the undercliff. Soon thereafter a crack measuring about 0.3 m in width with a vertical displacement of 0.4 m, and sympathetic cracking occurred sub-parallel to the shoreline at numerous locations across the undercliff area. A translational mass movement with a volume of approximately 18 million cubic meters was identified following the installation of inclinometers. Regrading of the spoil piles was designed and implemented causing the mass movement to stop. However, simplified and detailed slope stability analyses indicated that seismically-induced permanent slope displacements should be expected during significant earthquake events. A cumulative distribution function (CDF) that incorporated slope parameters and ground motion uncertainty was developed for slope displacements using the Newmark procedure. CDFs were developed conditional to the occurrence of the design earthquake events. Design displacements were selected based on owner risk tolerance and then incorporated into the design of the pipeline through: (a) the installation of a thicker wall at the location where displacements were expected; and (b) installation of an additional extensional loop on the pipeline. Shortly after completion of regrading to stabilize the mass movement, the slope was subjected to an M = 8.0 earthquake that caused permanent slope displacements in the range of 10 to 80 mm across the sliding plane. This paper describes slope performance from inclinometer and surface movement marker data following the M = 8.0 earthquake, comparison to the results of a probabilistic prediction of seismicallyinduced permanent slope displacements using simplified procedures, and discussion for the analysis and design of slopes subject to earthquake induced ground motions and incorporation into subsea design basis.

assignor to Schlumberger Technology Corporation 4 J .anuary 1983 (Class 367/34); flied 6 December 1979 This sonic logging tool consists of a transmitter and several receivers spaced one above the other. First portions of each received signal are correlated with each other using an assumed velocity, and the process is repeated using lesser and greater velocities. The best correlation is selected as the first provisional velocity. The process is repeated for second, third etc. portions of each waveform. The result is velocities for both the compressional and shear components of the acoustic wave.--TGW 4,364,033 43.40.Ph ALARMING SEISMOMETER Yun-Tyng Tsay, Taipei, Taiwan