Soil Borings Research Articles

Bacterial mutagenicity and acute toxicity of solvent and aqueous extracts of soil samples from an abandoned chemical manufacturing site

AbstractUsing a grid pattern, a total of 50 soil borings (DCT 1 through DCT 50) were collected from an abandoned chemical manufacturing facility. Split samples were obtained from six cores collected from a centralized location near a former wastewater lagoon. An additional sample from the 2.1‐ to 2.4‐m depth of core DCT 20 was obtained as representative of the waste present on site. Three subsamples from each of the six cores or a total of 18 samples were sequentially extracted with methylene chloride and methanol for testing in mutagenicity and acute toxicity assays. A separate batch extraction with water was conducted and evaluated, using both chemical and biological test methods. The maximum mutagenic response was 3,237 net revertants induced with metabolic activation by 1 mg of the methanol extract of the 0‐ to 0.6‐m depth at sampling location DCT 32. The water extract of the 0‐ to 0.6‐m depth at sampling location DCT 32 induced 737 net revertants per mg. At sampling location DCT 24, the water extract induced 0.74, 1.32, and 2.5 toxic units in the Microtox® assay and 935, 69, and 39 net revertants per mg in the mutagenicity assay at the 0‐ to 0.3‐, 1.2‐ to 1.4‐, and 2.1‐ to 2.4‐m depths, respectively. The chemical analysis of the samples from location DCT 24 indicated that the concentration of 2,3,6‐trichlorobenzene acetic acid ranged from 16 ppm in the 0‐ to 0.3‐m depth and to 0.95 ppm and below the detection limits at the 1.2‐ to 1.4‐ and 2.1‐ to 2.4‐m depths. The methanol extract of the soil from the 0‐ to 0.3‐m depth induced 19.2 toxic units in the acute toxicity assay and 1,467 net revertants in the mutagenicity assay. These results suggest that the most accurate site assessment is obtained when a water extract is evaluated to measure leaching potential and a solvent extract is evaluated to determine the relative total hazard of the sample. In addition, the combined use of chemical analysis, mutagenicity, and acute toxicity bioassays provides more accurate information from which to make a risk assessment.

Ground-water-quality assessment of the West Bountiful municipal landfill : Shank, D L Proc Symposium on Geology and Hydrology of Hazardous-Waste, Mining-Waste, Waste-Water and Repositories Sites in Utah, Salt Lake City, 1989P183–189. Publ Salt Lake City: Symposium and Field Conference, 1989 (Utah Geological Association Publication 17)

Abstract The West Bountiful Landfill occupies approximately 150 acres on the eastern shore of the Great Salt Lake in Davis County, Utah. The landfill has received municipal waste since about 1962 from 6 nearby municipalities and Davis County. Since about July 1987, the landfill has been operated solely by the City of Bountiful. To provide site-specific information regarding the potential for off-site movement of contaminated ground water, James M. Montgomery, Consulting Engineers, Inc. performed a Ground-Water-Quality Assessment study. To generate data necessary for this study, an extensive field investigation program was developed which consisted of drilling and sampling 7 perimeter soil borings to depths from 35 to 45 feet, constructing piezometers in each of these borings, and installing 8 new shallow monitoring wells. In addition, ground-water samples were collected from both the 8 new and 4 previously existing monitoring wells. The geologic conditions which underlie the West Bountiful Landfill are similar to those found in many locations along the shores of the Great Salt Lake. The landfill is underlain by interbedded layers of fine-grained soil such as clay and silt with occasional fine-grained sand and silty sand layers which range from thin laminae to 3.5 feet thick. Evidence suggesting lateral continuity of at least some of the individual layers was found in an areally extensive clay marker bed which was identified beneath the landfill in all of the 8 borings drilled at the site. Ground water beneath the West Bountiful Landfill occurs in fine sand and silty sand layers at various depths and in the refuse. The pattern of ground-water flow is generally from east to west in both the shallow zones, 8 to 12 feet below ground, and in deeper sand layers at depths of up to 40 feet below ground. Ground-water levels within the landfill refuse are elevated above the surrounding areas and create a ground-water mound. The difference between water levels in the ground-water mound and surrounding areas cause gradients to induce ground water to flow radially from the center of the landfill. Ground-water levels measured in piezometers indicate that the hydraulic head increases with depth which indicates that an upward vertical gradient underlies the landfill. The findings of this Ground-Water-Quality Assessment indicate that subsurface conditions beneath the site make it generally suitable for a municipal waste landfill. The low permeability clay layers which underlie the site appear to isolate the refuse and leachate from deeper aquifers. In addition, upward hydraulic gradients also tend to prevent a downward migration of leachate. However, leachate appears to migrate from the refuse into the Great Salt Lake through shallow, water-bearing zones.

New Depositional Model for the Mississippi River Delta Plain

The current Mississippi River delta plain model depicts a single Holocene delta plain consisting of six delta complexes sequentially deposited over the last 7000 years by the classic delta switching process. In order of increasing age, these complexes are the Atchafalaya, Balize, Lafourche, St. Bernard, Teche, and Maringouin. Between 1981 and 1986, the Louisiana Geological Survey has acquired more than 10,000 km of high-resolution seismic profiles, 248 offshore vibracores, 397 onshore vibracores, 234 soil borings, and 226 new radiocarbon dates throughout south Louisiana. Analysis of this data set led to the development of a new, more precise stratigraphic model which depicts the Mississippi delta plain as actually two individual, imbricated shelf-phase delta plains deposited at different sea level stillstands. Termed the Modern and Late Holocene, these two delta plains are separated by a ravinement surface several hundred kilometers in extent that can be traced updip to a relict-transgressive shoreline, termed the Penchant Shoreline. The Late Holocene delta plain consists of a set of delta complexes 15-20 m thick deposited during a sea level stillstand 6 m below the present, 4500-7000 y.B.P. This unit consists of the exposed Maringouin and Teche delta complexes offshore of south-central Louisiana and an unnamed deltamore » complex buried by the Modern delta plain in southeast Louisiana. A relative sea level rise between 2800-4500 y.B.P. to about present sea level led to the transgressive submergence of the Late Holocene delta plain, generating Trinity Shoal, Ship Shoal, and the Penchant Shoreline, which represents the subsurface eastern extension of the Vermilion Bay shoreline. The 10-15-m thick Modern delta plain began building seaward of the penchant Shoreline about 2800 y.B.P.« less

Necessary Redundancy in Geotechnical Engineering

The causes of geotechnical engineering failures are listed and discussed. Many of these could have been prevented or damages mitigated if redundancy had been used in design and construction. Redundancy is defined in special terms applicable to geotechnical engineering. How redundancy can and should be used in preliminary exploration, soil borings, laboratory testing, analysis, design, and construction is discussed. Eight cases of failure are discussed and analyzed in which lack of redundancy led to the failures. In each case it is shown how redundancy in at least one of the forms discussed could have prevented failure.

Soil gas survey techniques for the investigation of underground storage tanks

AbstractThe sampling and analysis of near surface soil gas has shown great promise for the investigations of underground storage tanks. Trace to elevated concentrations of volatile organic components in soil gas samples have been used to identify source areas near buried tanks and map the migration of releases in groundwater and in the vadose zone. Soil gas surveys are also an effective tool to position soil borings, excavations, and monitoring wells, while support equipment (drilling rigs, backhoe, etc.) is still on site. Two examples are presented where soil gas surveys were used to direct the investigation of underground storage tanks.

Landslide investigation utilizing electric cone penetration testing : French, J; Kropp, A In: Use of In Situ Tests in Geotechnical Engineering (papers to the Conference, Blacksburg, 23–25 June 1986)P529–545. Publ New York: ASCE, 1986 (ASCE Geotechnical Special Publication No 6)

A geotechnical investigation was conducted of landsliding at a hillside residential property to evaluate both the extent of the landslide and the stability of the fill materials as well as to provide recommendations for remedial work to stabilize the property. Conventional techniques were used to explore the site but were supplemented with cone penetration testing. The cone penetration work was performed to help locate the thin landslide slip planes and to evaluate the quality of the fill material present. By comparing the information from the conventional soil borings with the data from the cone penetration tests the primary slide plane was found, additional potential slide planes were located, patterns of subsurface variation were determined, and variability of individual lifts of fill materials was discovered.

Quality in soil borings makes a difference : Dover, A R; Audibert, J M E; Bea, A G Oil Gas J, V79, N26, 29 June 1982, P133–139

Quality in soil borings makes a difference : Dover, A R; Audibert, J M E; Bea, A G Oil Gas J, V79, N26, 29 June 1982, P133–139

Description and dating of a submerged beach in the northern North Sea

An assumed submerged beach, bordering the northern part of the North Sea Plateau towards the Norwegian Trench at 130 to 160 m waterdepth, has previously been described based on interpretation of seismic profiling. The seismic unit is parallel to the edge of the plateau for at least 50 km, with an eastward-dipping bedding. Soil borings and vibrocorer samples reveal that a stiff to hard clay is overlain by a thin lag deposit of coarse material on the plateau, by an up to 40 m-thick coarsening-upwards sequence of sand and gravel on the upper part of the slope and by gradually finer material further eastwards in deeper water. A low sea level is also indicated by the foraminiferal faunas, and abundant littoral and aeolian textures on quartz sand grains. Nine radiocarbon datings of shell material, found in sand and gravel from about 1 to 23 m below the sea bed, gave ages from 10,800 to 12,500 yrs B.P. We thus consider the interpretation of the edge of the plateau and the top of the slope as a submerged beach built out in Late Weichselian time to be confirmed by the sample evidence.

Recent sedimentation, northeastern Port Valdez, Alaska

Sediments accumulating on the northeastern shore of Port Valdez, a fjord leading to Prince William Sound in southern Alaska, are derived from both deltaic and alluvial fan processes. The resulting thick wedge of Recent silts, sands, shells and gravels lies atop irregular ridges of local graywacke bedrock and scattered till deposits. Seismic reflection profiling augmented by soil borings indicates that rapid infilling and upbuilding has occurred at this site. Evidence of slumping suggests general instability of steep submarine slopes in an area characterized by strong earthquakes and large tidal ranges.

North Sea Foundation investigation techniques

Abstract Foundation investigations for large platforms in the harsh North Sea environment are costly, consequently, investigations are undertaken in progressive stages so that structural concepts can be developed with due regard to soil conditions. The shallow geological environment surrounding a platform site is explored by high resolution geophysical techniques, and interpretation of the seismic profiling data can be improved when results from one or two soil borings are available for correlating strati‐graphic boundaries. Geotechnical properties of soils and rocks to penetrations of 150 m are determined from laboratory testing of recovered samples and from in situ testing. Deep penetration push sampling and cone penetrometer testing have been conducted with the recently developed Stingray system. Sampling technique has no marked effect upon the shear strength of heavily overconsolidated North Sea clays but wireline percussion sampling reduced soil stiffness by 25 to 50 percent. Continuous in situ cone ...

North sea foundation investigation techniques

Abstract Foundation investigations for large platforms in the harsh North Sea environment are costly, consequently, investigations are undertaken in progressive stages so that structural concepts can be developed with due regard to soil conditions. The shallow geological environment surrounding a platform site is explored by high resolution geophysical techniques, and interpretation of the seismic profiling data can be improved when results from one or two soil borings are available for correlating strati‐graphic boundaries. Geotechnical properties of soils and rocks to penetrations of 150 m are determined from laboratory testing of recovered samples and from in situ testing. Deep penetration push sampling and cone penetrometer testing have been conducted with the recently developed Stingray system. Sampling technique has no marked effect upon the shear strength of heavily overconsolidated North Sea clays but wireline percussion sampling reduced soil stiffness by 25 to 50 percent. Continuous in situ cone ...

Evaluation of Nematic1Des/Insecticides for Sweet Potato, Wayne County, 1978

Abstract The effects of fumigant and non-fumigant nematicides/insecticides on nematodes and soil insects, yield, and quality of sweet potatoes were studied in a deep Norfolk sandy loam (pH = 6.4; O. M. = 0.5%; sand = 85.2%, silt = 10.1%, clay = 4.7%) in Wayne County, NC. The site had been planted to sweetpotatoes in 1977 and soybeans in 1976; root-knot nematode larvae counts of ca. 100/500 cm3 soil were low on May, 1978. On Jun 7, plots were hilled, and Vernam 6EC herbicide (.66 pt/acre) was applied. On Jun 14, fumigants were injected with a single chisel at a depth of ca. 6 inches centered over the row using a self-propelled applicator. Soil temperature at 6-inch depth was 83°F, air temperature was 90°F, and soil moisture was 85.3% of field capacity. On Jun 28, granular formulations were uniformly applied with a “salt shaker#x201D;, and wettable powders were suspended in water and applied as a drench at a rate of ca. 500 gal/acre or were applied with transplant water. Granular materials and drenches were applied to a 12-inch band over row centers, and within an hour incorporated to a depth of ca. 6-8 inches using a rototiller. Soil temperature at a 6-inch depth was 88°F, air temperature was 95°F, and soil moisture was fairly dry (77.6% of field capacity). On Jul 24, at layby, granular materials were uniformly applied to a 12-inch band over plant canopy using a “salt shaker#x201D;. Plots were single rows, 50-ft long, on 40-inch spacing. Treatments were replicated in four complete randomized blocks with 10-ft alleys between replications. On Oct 23, twelve soil borings (2 to 12-inch horizon) were taken from the root zone of each plot, composited, assayed for nematodes (extracted by the elutriation-centrifugation technique) and identified. On Oct 24, roots were harvested, graded into U.S.D.A. size grades (Jumbo, No. 1, Conner), and weighed; fifteen roots (5 canner, 5 small and 5 medium No. 1) were removed from each plot and rated for nematode, wireworm, white grub, and flea beetle damage; internal nematode infection was counted by slicing ca. 40% of the distal portion of each root in 2-mm sections and counting internal lesions. Weather during growing season was dry, and plants were under moisture stress in late summer. There was no water injury to roots at harvest as had occurred in previous years.

Pullout Tests of Grouted Piles in Stiff Clay

This paper describes pullout tests that were conducted in stiff clay near Austin, Tex., to determine the tension capacity of grouted piles and to assess the effect of lateral loading on pullout resistance. In some tests, failures occurred at the pile-grout interface with maximum shearing stresses of 30 psi. In most tests, failures occurred at the grout-soil interfaces with shearing stresses of 50 percent of the soil-shear strength. Introduction Pullout tests on grouted piles in stiff clay were run at a site Pullout tests on grouted piles in stiff clay were run at a site 5 miles northeast of Austin, Tex., adjacent to U.S. Highway 290. The pullout tests followed a series of lateral-load tests on 6- and 24-in.-diameter pipe piles. Four W-piles were routed in drilled holes to serve as anchors for a reaction frame used during the lateral-load tests. After these tests, three W-piles were pulled in the investigation of the strength of grouted piles. In addition, pull tests were made on two 16-in.-diameter pipe piles pull tests were made on two 16-in.-diameter pipe piles that were grouted in drilled holes. The tests on pipe piles were made before and after lateral loadings. Soil Investigations Nine soil borings were made at the test site to provide information for the lateral and pullout test. Details of these borings and of the preparation of the test pit were reported previously and are not repeated here. The bottom of the test pit was approximately 6 ft below the original ground surface. The pit had been inundated 9 months before the first pullout tests. A composite profile of soil types, Atterberg limits, and shear strengths of the stiff clay is given in Fig. 1. To represent the in-situ properties of the clay, the following distribution of shear strength with depth was selected. Undrained Depth Shear Strength (ft) (tons/sq ft) --------- ----------------------- 0 0.1 1 0.8 13 3.5 21 3.5 31 12.4 Installation of W-Piles A plan of the test pit is given in Fig. 2, indicating locations of the three W-piles (W-1, W-2, and W-3) and of the two pipe piles (P-1 and P-2). In addition, locations are indicated for five of the nine soil borings. Boring 9 located 2 ft from Pile P-2 was taken 3 months after the pullout tests. The 24-in.-diameter pipe piles used for pullout tests. The 24-in.-diameter pipe piles used for the lateral-load tests are designated as Pile 1 and Pile 2 in fig. 2. The W-piles were 14 in. deep with a 12-in. flange, and weighed 78 lb/ft. Two piles (W-1 and W-3) were installed in holes that had been drilled wet with a fishtail bit and Pile W-2 was installed in a hole that had been dry augered. The holes were approximately 25 in. in diameter and 30 ft deep, After the holes had been drilled, the W-piles were lowered into the holes through a template to assure proper positioning. Concrete with a mix ratio of 1:2:2 by weight positioning. Concrete with a mix ratio of 1:2:2 by weight of cement, sand, and gravel, respectively, then was placed into the holes using a 20 ft-long tremie pipe. For placed into the holes using a 20 ft-long tremie pipe. For ease in placing concrete, the maximum gravel size was 3/4 in. The placement of concrete continued until returns were received at the ground line. The concrete had a 7-day compressive strength of 3,020 psi with an estimated 28-day compressive strength of 4,530 psi. Concrete was not placed along the total 30-ft penetration of the W-piles. The grouted lengths for Piles W-1, penetration of the W-piles. The grouted lengths for Piles W-1, W-2, and W-3 were 20, 27, and 24 ft, respectively. These grouted lengths were determined at the end of pullout tests when the piles were salvaged. JPT P. 349

On-Bottom Pipeline Stability in Steady Water Currents

A recommended practice is established for the on-bottom stability design of a submarine pipeline subjected to steady water currents. A parametric study indicates that the minimum specific gravity required for stability is relatively insensitive to large variations in the value of most parameters in the design equations. The design graphs presented can be used for most pipeline stability design problems. pipeline stability design problems. Introduction The design of an offshore pipeline system must consider the following factors. Operating requirements. such as internal pressure, throughput, and so forth, influence the design greatly. At the same time, the design must provide for the safety and integrity of the pipeline when faced with external and environmental factors during the expected lifetime of the system. Factors influencing the selection, design, and efficiency of the construction system also must be included in the over-all design. The specifications for the line pipe and the pipe-coating system must not exceed those required to pipe-coating system must not exceed those required to assure adequate operating performance and long-term line safety. Unnecessary pipe weight and too-stringent pipe-handling criteria impose restrictive operating limits on pipe-handling criteria impose restrictive operating limits on present construction systems, even in moderate water present construction systems, even in moderate water depths. In deeper water, these criteria may impose impractical requirements on the construction system. The selection of the pipe and specifications for the coating system are affected directly by the criteria established for the maximum environmental conditions expected during the life of the pipeline. Therefore, the environment of the operating pipeline is the starting point of the design. A complete discussion of the environment near the sea-water/soil interface is beyond the scope of this study. However, certain environmental situations must be avoided by careful route study and selection because there is no known method to ensure pipeline stability and integrity when faced with gross instability of the sea bottom. Thus, route selection is the most important step in stability design. Mes gives a general discussion of the ocean bottom needed for design purposes and methods of obtaining the necessary data. Bea et al. in their discussion of bottom movements in the Mississippi Delta present an excellent example of the correlation of present an excellent example of the correlation of bathy-metric surveys, soil borings, sparker data, and the general geology of a given area. Studying the available data is a prerequisite to rational route selection. Once a route has been selected to avoid hazardous environmental factors, the designer then investigates the local, rather than the large scale, environment of the pipeline. First, he asks whether the bottom is locally pipeline. First, he asks whether the bottom is locally stable. Will scour occur? This important question is not considered in this study. Townsend and Farley conducted scour tests in noncohesive soils and concluded that a pipeline would settle and remain in contact with the sand bottom as it eroded. The same conclusion was reached earlier from unpublished tests conducted by the Shell Pipeline Research and Development Laboratory. Of course, if portions of the pipeline are placed on harder or nonscouring materials, then a span can remain suspended over other bottom portions that do scour. Also, this study does not consider the magnitude of the hydrodynamic forces exerted on the pipeline by surface waves. Grace has summarized available wave-force data through 1973 for submarine pipelines. Although wave forces can be as significant as those resulting from steady currents, this investigation only is concerned with the hydrodynamic forces exerted by steady currents. P. 475

Movement of sediment on the Gulf of Mexico, continental slope and upper continental shelf

Abstract Grain size, coarse fraction analyses, and depositional environment as interpreted from microfauna are related to the character of sparker reflections at the location of core holes drilled by Exxon, Chevron, Gulf, and Mobil on the continental slope of the northern Gulf of Mexico. Continuous sparker reflections are correlated with slowly deposited, evenly bedded sediments containing bathyal faunas. The coarse fraction is dominated by the tests of foraminifera. Discontinuous, discordant reflections and diffractions are correlated with sediments more rapidly emplaced in the bathyal environment of the continental slope by slumping and sliding from the continental shelf. Their coarse fraction is dominated by terrigenous sand grains. A large portion of the volume of continental slope sediments appears to consist of these “displaced”; sediments, including an area 3–24 km wide and 80 km long, southeast of Corpus Christi, Texas. Comparable processes of movement of sediments are interpreted on the continental shelf south of the Southwest Pass of the Mississippi River. Bathymetry in this area is characterized by a series of subaqueous “gullies”; radiating from the river mouth and leading to terraces at their southern extremities. Side‐scan sonar and PDR surveys show a rough bottom in these “gullies”; and terraces, as contrasted with a relatively smooth bottom elsewhere. The rough bottom is interpreted as indicative of slump and creep of the sediments from shallower water. Some foundation soil borings in this area south of Southwest Pass find a low‐strength material gradually increasing in strength with depth. Other borings find a “crust”; of anomalously strong material 8–15 m below the mudline. The microfauna recovered from the “crust”; has moved to its present position by slump or creep from shallower water along a pattern comparable to the gullies shown in the present‐day bathymetry.

Evaluation of Nematicides and Insecticides for Sweet Potatoes, 1975

Abstract The effects of fumigant and nonfumigant nematicides and insecticides on nematodes, and insects, and on yield and quality of sweet potatoes were studied in a deep Norfolk Sandy Loam (pH = 6.0, O. M. = 0.7%, silt = 85.2%, sand = 10.1%, clay = 4.7%). The site had been planted to tobacco the previous year. A moderate infestation of root-knot nematode larvae (ca. 1000/cc soil) was present in March, 1975. On June 3, the field was disked. On June 4, 7-day preplant treatments were applied; soil temperature at 4 in. was 84°F, moisture was estimated at 90% of field capacity. On June 11, at planting treatments, Vernam 6EC herbicide (2/3 pt/A), and fertilizer (500 lb/A 6-12-6) were applied, and sweet potato plants free of nematode infection were planted. Soil temperature was 76°F at 4 in., moisture was estimated at ca. 50% of field capacity. Granular products were broadcast over proper plots, mixed in the top six inches with a “roto-tiller”; in-row applications were banded 12-inches wide and bedded up. Telone was placed 6-inches deep with a hand injector on 12-inch spacing in the row. Emulsifiable concen-trates were disolved in ca. 1.9 gal of water (500 gal/A) and drenched over proper plots. Plots were single rows, 50 ft long on 40-inch centers with ca. 12-inch spacing between plants. Treatments were randomized in four blocks. On July 29, layby treatments were broad-cast over the plants. On September 3, twelve soil borings (2 to 12-inch zone) were taken in each plot, composited, and assayed for nematodes (extracted by sugar solution flotation technique), and on October 8, roots were harvested and yields were recorded in pounds by U.S.D.A. size grades (jumbo. No. 1, canner). Nematode infestation was counted by slicing 1/3 to 1/2 of the distal portion of the root in 2-mm sections from five roots in each grade and counting internal lesions. Insect damage and overall quality were assessed visually. The root-knot level was high and wireworm injury was moderate. The growing season was normal and plants were not subject to prolonged drought stress. Moderate rains prior to harvest caused some roots to rot.

The Failure of the South Pass 70 Platform B in Hurricane Camille

In Aug. 1969 Shell Oil Co.'s Platform B, located in the OCS-designated South Pass Block 70, went down in Hurricane Camille. An intensive study was undertaken to determine the cause of platform failure. The data conclusively show that the structure failed primarily because of sea-floor soil movement. Introduction South Pass Block 70 is located about 15 miles southeast of the Main Pass on the Mississippi River (see Fig. 1). In preparation for the installation of a platform at this location, soil borings were taken by the well-known wireline technique. While experience in the Delta region led us to expect low soil strengths, the extent and depth of the very weak clays that were found in the boring program were unexpected. An immediate concern revolved around appropriate design approaches to withstand lateral and axial pile loadings. A second, and ultimately much more serious problem, was soon hypothesized; the soils were so weak that soil movement caused by slumping or sliding actions might take place. Thus, while the design proceeded, a program of research and field work to evaluate the probability of sea-floor movements was undertaken. The first public discussion of the potential problem was presented in 1970. Since that time, other investigators have studied the problem. The major conclusion of the initial engineering study and research was that waves in a major hurricane could cause sufficient bottom pressures to create soil instability. This situation, however, could only be developed in severe hurricanes occurring about once in a hundred years or greater, and would not occur under normal sea conditions or moderate storms. Accordingly, the decision was made to design the structure using the once-in-a-hundred-years wind and wave. Because of the very weak near-surface soils, the bottom of the structure was extended into the soil (see Fig. 2). This extension provided for increased stability during installation and reduced lateral deflections under wave loading. Hurricane Camille formed in the western Caribbean during the morning of Aug. 15, 1969. The eye of the storm, following the path shown in Fig. 1, crossed the Mississippi Gulf Coast on the evening of Aug. 17. Shell's South Pass 70 Platform B was destroyed in this storm, as was the Gulf Oil Co. South Pass 61 platform. Pass 61 platform. Investigation Program After Hurricane Camille, an intensive investigation was initiated to determine the cause of failure of the South Pass 70 Platform B. The investigation included above-water inspection of several adjacent platforms, the use of side-scan sonar to get a post-Camille picture of the South Pass 70 Platform B structure, a series of topographical surveys to compare with pre-camille conditions, several post-Camille soil borings to compare with pre-camille post-Camille soil borings to compare with pre-camille conditions, and a detailed diving and underwater television inspection of the fallen Platform B. Results and Interpretations Above-Water Inspection Seven major platforms in the general area were visited by a team of offshore-platform design engineers. Their main purpose was to ascertain the above-water damage at each site and to establish, where possible, the maximum wave crest reached on each platform. JPT P. 263

Policing the financial marriage

One of the most difficult types of financial marriages is the joint venture between a real estate developer and a financial partner. In a sense, all real estate development is a joint venture, but some classes of real estate investors are accustomed to the arrangements and know how to administer investments. Institutional lenders fall within this group. Corporate investors are less well-prepared, but have made and are making good joint ventures; their institutional character typically assures reasonable review, care, and control. The least well-qualified financial partner is an individual or a group of individual equity investors. These partners are willing to take risks and are often less sophisticated than institutional sources of equity capital. This class of investors may represent the last hope for developers refused by institutional sources of equity capital, but may be the first choice of other developers because of the ease with which some individuals can be persuaded. For individual investors, the incentive for real estate investment is the availability of excellent tax-sheltered returns, a benefit less valued by institutions. A joint venture begins when a real estate developer selects a parcel of land to develop and ties it up with either an option or some type of sales contract, often conditional on rezoning. A title search is made and title problems evaluated. The market is studied by more sophisticated developers; land and building absorption rates are established to form a marketing plan. An engineering plan is then developed to implement the marketing plan. This provides for earth moving, relocation of electric cables, extension of utilities, soil boring, a circulation plan if the development is large, and, perhaps, a dam, bridge, or lake. A zoning presentation is usually underway at the same time, because few larger properties or projects can proceed without some type of zoning adjustment. Approval often is tied to approval of a transportation plan showing where the proposed development will tie into the circulation system of the community and which roads will be dedicated for public use. Concurrently, the developer should be preparing detailed cost estimates on the first phase of development. This will include the cost of structures, financing, overhead, carrying charges, and profits. He then estimates his 79

Effects of site and propagation path on recorded strong earthquake motions

Abstract Accelerograms from the 1952 and 1954 Kern County and the October 1933 Signal Hill earthquakes were used with detailed site models in an attempt to isolate the principal site, path, and source contributions in the recorded motions. Site models 20,000 ft deep were developed from soil, water and oil borings, geological reports, and near-surface refraction surveys at four accelerograph sites in Los Angeles and one at Taft, California. Analysis was based on linear system theory, using Fourier spectra and hypothesizing vertically incident shear waves. The four subsurface site models at Los Angeles were adjusted within the uncertainties of the model properties to minimize the standard deviation of computed 1952 bedrock motions. These stations were close together relative to the epicentral distance. Resulting subsurface transfer functions showed, generally, highest amplifications at the Hollywood station and lowest at UCLA, with a 100 per cent range based on the latter. Attenuation in the crustal path was evaluated using computed bedrock motions and incorporating the data at Taft. The exponent of distance for geometrical spreading was close to minus one. The damping along the path, expressed as Q, was 550 for the 1952 case and 62 for the 1933 case. A spectrum was obtained for the ratio of the source functions for the 1952 and 1954 earthquakes.

Khazzan Dubai No. 1: Pile Design and Installation

Khazzan Dubai No. 1, the first offshore oil storage tank of its kind, relies on a skirt pile anchorage system for its support. The 500,000 barrel tank, submerged in 154 ft of water, is now in service for Dubai Petroleum Company, 60 miles offshore from the Trucial State of Dubai. The foundation must support the massive weight of the structure, overcome the buoyancy of the stored oil, and resist severe environmental forces created by design waves over 39 ft high. Design of the piling was based on soil properties determiend from an exploratory site investigation, including detailed soil borings. The 36-in. diameter steel piles were placed in oversized holes drilled into the sea floor, and grouted to the soil formation and to the structure. A pullout test of a full-scale pile was performed on site to substantiate the design basis.