carry out a work unit under the Construction, Operation, and Maintenance 

 Research Area titled "Rehabilitation of Rubble-Mound Structure Toes." The 

 prime objective of this work unit is to develop guidelines for repair and/or 

 rehabilitation of rubble-mound structure toes. This will be accomplished 

 through conduct of the following four work phases: 



a. Through telephone contacts with design, construction, and opera- 

 tions personnel in the Corps' division and district offices it 

 will be determined where structures exist that have, are felt to 

 have, or have had toe-related stability problems. Once this is 

 accomplished, follow-up visits will be made to the division and 

 district offices to gain a better understanding of the problems, 

 and the steps that were taken (if any) to alleviate the prob- 

 lems, and the relative success or failure of the repair or 

 rehabilitation work. 



b. Once an overall understanding is gained of the various toe 



~ stability problems confronting field designers, they will be 

 categorized according to type. Subsequent to this, general 

 experimental model testing programs will be developed to address 

 the various problem types. The goal of these tests will be to 

 experimentally determine and document improved methodologies 

 through which successful toe repair and rehabilitation work can 

 be designed and carried out. 



c. The experimental model tests (both two- and three-dimensional) 

 will be carried out over a 2-year period. During this time, the 

 scope of the tests will be subject to periodic changes based on 

 continued information obtained and additional understanding 

 gained on the problems confronting field personnel. 



d. A thorough analysis of the data compiled during the model tests 

 will be carried out in an effort to produce general rubble-mound 

 toe repair, and rehabilitation guidelines and a comprehensive 

 report covering the model tests and presenting the experi- 

 mentally developed guidance will be prepared and published. 



Item a has been completed and is reported herein. Continued efforts will be 

 made to maintain contact with and to obtain additional information from field 

 personnel faced with rubble-mound toe stability problems. Item b has been 

 completed for the presently available data, and two-dimensional experimental 

 model tests (Item £) have been developed and initiated. A three-dimensional 

 test series (Item £) is being developed based on findings of the two- 

 dimensional tests. As previously stated. Item b and, in turn. Item c are 

 subject to change as more field experience information becomes available. 



