Small-Scale Evaluation Of Engineered Anti-Ram Rock Barrier Systems In Cohesionless Soil

Open Access
Author:
Hoskins, Samuel Paul
Graduate Program:
Mechanical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
None
Committee Members:
  • Sean Brennan, Thesis Advisor
Keywords:
  • Small-Scale
  • Anti-Ram Rock Barrier
  • Cohesionless Soil
Abstract:
This thesis focuses on anti-ram barriers that are made from natural boulders that may or may not have simple modifications. Testing an anti-ram barrier is by nature destructive and costly, so previous research [1] developed and validated scaling of the tests. This thesis utilizes this small-scale testing capability to examine many methods and systems for modifying natural boulders as anti-ram barriers. To obtain perspective on this scaling, a full-scale boulder barrier that was able to achieve a M30 pass rating as an anti-ram barrier has a mass of 9,750 kg, while its small-scale equivalent has a mass of 11.8kg. A goal of this thesis is to provide design guidance to determine which devices should be evaluated in full-scale testing, based on the lessons learned from small-scale testing. The simplest barrier design considered herein is a very large boulder that can dissipate the energy of the impacting vehicle. However, such boulders are quite large and difficult to install. This thesis explores engineering solutions that produce smaller rock barriers that yield similar or better results than the large rock barriers. Additionally, this thesis explores methods to evaluate the potential of rock barrier failure due to fracture of the rock. The evaluation process is based upon small-scale experimental tests of various rock samples. The end results of this research are realization of several methods to enhance the ability of boulders to arrest the progress of an impacting vehicle. These enhancements include performance improvements; for example, some of the engineered systems in this study improve the results of a single boulder design by reducing post-impact rotation by 42%. Other designs improve the efficiency of installation, saving substantial time and money yet having end results that are similar in performance to the baseline design. Overall, this research shows that it is possible to use smaller, more cost-effective boulder designs as part of an engineered system to impede an impacting vehicle.