Please use this identifier to cite or link to this item: https://hdl.handle.net/11681/20980
Title: Properties of expansive clay soils. report 2, a numerical procedure for predicting heave with time
Authors: Johnson, Lawrence D.
Desai, C. S. (Chandrakant S.), 1936-
Keywords: Computer programming
Heaving
Expansive clays
Numerical methods
Numerical models
Finite difference method
Soil swelling
Foundation investigations
Soil mechanics
Publisher: Soils and Pavements Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Miscellaneous Paper (U.S. Army Engineer Waterways Experiment Station) ; S-73-28 Rept.2
Description: Miscellaneous Paper
Abstract: A relatively economical and expedient numerical procedure and computer code based on the finite difference method were developed for predicting heave with time for heterogeneous expansive soils beneath structures idealized as two-dimensional. The computer code will also compute the potential heave assuming saturation of the foundation soils based on McDowell's swell data. The heave with time estimates should be useful for structures near which penetration of rainwater from the ground surface is permitted, provided that ponding of surface water and external water from leaking water and sewer lines does not occur. The potential heave should be useful if the foundation soils become saturated from excessive watering, poor surface drainage, and leaking water and sewer lines. The required input data include the structural load, specific gravity, liquid and plastic limits, initial dry density and water content, coefficient of vertical permeability, ratio of the horizontal to the vertical coefficient of permeability, and swell and suction relationships of the foundation soils. The swell and suction data in this report were adopted from published literature and were represented in the code by using a bicubic spline function. The remaining input data can be obtained from relatively simple laboratory tests. The procedure was applied to the prediction of heave with time for two field problems. In view of the approximate nature of the adopted swell and suction data, the heave predictions and extents of active zones influenced by heave show reasonable agreement with field observations. Field conditions that include the drainage pattern, amount and frequency of rainfall, and soil temperature were ignored. The suction computations suggest existence of perched water tables, which were confirmed by field piezometric data. The predicted heaves with time were substantially less than heaves determined by assuming completely saturated foundation soils and were relatively insensitive to the ratios of the horizontal to vertical coefficients of permeability. Further field data and results of swell and suction tests on undisturbed soils will be necessary to verify the generality of the formulation and code.
Gov't Doc #: Miscellaneous Paper S-73-28 Rept.2
Rights: Approved for public release; distribution is unlimited.
URI: http://hdl.handle.net/11681/20980
Appears in Collections:Miscellaneous Paper

Files in This Item:
File Description SizeFormat 
MP-S-73-28-Report-2.pdf7.67 MBAdobe PDFThumbnail
View/Open