dc.contributor.author	Green, Russell A.	en
dc.contributor.committeechair	Mitchell, James K.	en
dc.contributor.committeemember	Obermeier, S. F.	en
dc.contributor.committeemember	Singh, Mahendra P.	en
dc.contributor.committeemember	Kuppusamy, Thangavelu	en
dc.contributor.committeemember	Martin, James R. Jr.	en
dc.contributor.committeemember	Gutierrez, Marte S.	en
dc.contributor.department	Civil Engineering	en
dc.date.accessioned	2014-03-14T20:15:09Z	en
dc.date.adate	2001-08-14	en
dc.date.available	2014-03-14T20:15:09Z	en
dc.date.issued	2001-08-06	en
dc.date.rdate	2002-08-14	en
dc.date.sdate	2001-08-13	en
dc.description.abstract	Remedial ground densification is commonly used to reduce the liquefaction susceptibility of loose, saturated sand deposits, wherein controlled liquefaction is typically induced as the first step in the densification process. Assuming that the extent of induced liquefaction is approximately equal to the extent of ground densification, the purpose of this research is to assess the feasibility of using earthquake liquefaction data in remedial ground densification design via energy-based concepts. The energy dissipated by frictional mechanisms during the relative movement of sand grains is hypothesized to be directly related to the ability of a soil to resist liquefaction (i.e., Capacity). This hypothesis is supported by energy-based pore pressure generation models, which functionally relate dissipated energy to residual excess pore pressures. Assuming a linearized hysteretic model, a "simplified" expression is derived for computing the energy dissipated in the soil during an earthquake (i.e., Demand). Using this expression, the cumulative energy dissipated per unit volume of soil and normalized by the initial mean effective confining stress (i.e., normalized energy demand: NED) is calculated for 126 earthquake case histories for which the occurrence or non-occurrence of liquefaction is known. By plotting the computed NED values as a function of their corresponding SPT penetration resistance, a correlation between the normalized energy capacity of the soil (NEC) and SPT penetration resistance is established by the boundary giving a reasonable separation of the liquefaction / no liquefaction data points. NEC is the cumulative energy dissipated per unit volume of soil up to initial liquefaction, normalized by the initial mean effective confining stress, and the NEC correlation with SPT penetration resistance is referred to as the Capacity curve. Because the motions induced during earthquake shaking and remedial ground densification significantly differ in amplitude, duration, and frequency content, the dependency of the derived Capacity curve on the nature of the loading needs to be established. Towards this end, the calibration parameters for energy-based pore pressure generation models are examined for their dependence on the amplitude of the applied loading. The premise being that if the relationship between dissipated energy and pore pressure generation is independent of the amplitude of loading, then the energy required to generate excess pore pressures equal to the initial effective confining stress should also be independent of the load amplitude. However, no conclusive statement could be made from results of this review. Next, first order numerical models are developed for computing the spatial distribution of the energy dissipated in the soil during treatment using the vibratory probe method, deep dynamic compaction, and explosive compaction. In conjunction with the earthquake-derived Capacity curves, the models are used to predict the spatial extent of induced liquefaction during soil treatment and compared with the predicted spatial extent of improvement using empirical expressions and guidelines. Although the proposed numerical models require further validation, the predicted extent of liquefaction and improvement are in very good agreement, thus giving credence to the feasibility of using the Capacity curve for remedial ground densification design. Although further work is required to develop energy-based remedial densification design procedures, the potential benefits of such procedures are as follows. By using the Capacity curve, the minimum dissipated energy required for successful treatment of the soil can be determined. Because there are physical limits on the magnitude of the energy that can be imparted by a given technique, such an approach may lead to improved feasibility assessments and initial designs of the densification programs.	en
dc.description.degree	Ph. D.	en
dc.identifier.other	etd-08132001-170900	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-08132001-170900/	en
dc.identifier.uri	http://hdl.handle.net/10919/28641	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	17_Chapter_9.pdf	en
dc.relation.haspart	01_Cover.pdf	en
dc.relation.haspart	16_Chapter_8.pdf	en
dc.relation.haspart	06_Table_of_Contents.pdf	en
dc.relation.haspart	14_Chapter_6.pdf	en
dc.relation.haspart	03_Grant_Information.pdf	en
dc.relation.haspart	05_Acknowledgements.pdf	en
dc.relation.haspart	12_Chapter_4.pdf	en
dc.relation.haspart	11_Chapter_3.pdf	en
dc.relation.haspart	08_List_of_Figures.pdf	en
dc.relation.haspart	13_Chapter_5.pdf	en
dc.relation.haspart	18_References.pdf	en
dc.relation.haspart	10_Chapter_2.pdf	en
dc.relation.haspart	02_Abstract.pdf	en
dc.relation.haspart	09_Chapter_1.pdf	en
dc.relation.haspart	04_Dedication.pdf	en
dc.relation.haspart	15_Chapter_7.pdf	en
dc.relation.haspart	07_List_of_Tables.pdf	en
dc.relation.haspart	19_Vita.pdf	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	Earthquake	en
dc.subject	Energy	en
dc.subject	Liquefaction	en
dc.subject	Ground Improvement	en
dc.subject	Remediation	en
dc.subject	Densification	en
dc.title	Energy-Based Evaluation and Remediation of Liquefiable Soils	en
dc.type	Dissertation	en
thesis.degree.discipline	Civil Engineering	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	doctoral	en
thesis.degree.name	Ph. D.	en

Energy-Based Evaluation and Remediation of Liquefiable Soils

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