Creep behavior of soil nail walls in high plasticity index (PI) soils : project summary.

Details

• Creators:
  Sanchez, Marcelo ; Briaud, Jean-Louis ; Hurlebaus, Stefan ; Kharanaghi, Mohsen Mahdavi ; Bi, Gang
• Corporate Creators:
  Texas A&M Transportation Institute
• Contributors:
  Odell, Wade
• Corporate Contributors:
  Texas. Dept. of Transportation. Research and Technology Implementation Office
• Subject/TRT Terms:
  • Clay soils
  • Creep
  • Embankments
  • Load tests
  • Plasticity
  • Soil nailing
  • Tendons
  • Research
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Texas
• Corporate Publisher:
  Texas Department of Transportation. Research and Technology Implementation Office
• Abstract:
  Soil nailing is a convenient and economic ; stabilization method for the reinforcement of existing ; excavations by installing threaded steel bars into cuts ; or slopes as wall construction progresses from top ; down (Figure 1). An aspect of particular concern in ; the soil nail wall guideline is the creep behavior of ; this type of system in high-plasticity (HP) clays (i.e., ; those soils with a plasticity index greater than 20). ; However, soil nail walls have been constructed with ; success in HP soils (particularly in Texas), and no ; issues associated with creep behavior have been ; observed so far, including walls that were built more ; than 20 years ago. The main motivation of this ; research project is to gain a better understanding of ; the behavior of soil nail walls in HP clays and to ; suggest possible modification to the current ; guideline. ; In order to assess the effect of creep behavior in HP ; clays, the following tasks were conducted: ; 1. Pullout tests on eight existing anchors installed in ; 1991 at the clay site at the National Geotechnical ; Experimentation Site at Texas A&M University ; (NGES-TAMU) were performed to explore any ; effect on the bond strength related to long-term ; installation (i.e., soil ageing). ; 2. Pullout tests on 16 new vertical soil nails ; installed at the NGES-TAMU clay site were ; carried out following different protocols to learn ; about the effect of stress level on creep behavior. ; 3. Pullout tests on six new sacrificial nails installed ; at different heights in a new soil nail wall at ; Beaumont were carried out to learn about the ; nail creep behavior under actual conditions. ; 4. The actual soil nail wall was monitored at ; Beaumont (453 ft. long and 25 ft. high) for ; 13 months to learn about the service load in nails ; and different wall movements in time. ; 5. Laboratory tests (e.g., triaxial creep and ; oedometer tests) were performed on samples ; gathered from the two sites investigated in this ; project (i.e., NGES-TAMU and Beaumont). ; 6. Numerical simulations were conducted using ; FLAC-3D. All components of the soil nail wall ; were simulated. The simulations were first ; calibrated against the pull-out tests and lab data. ; Then the Beaumont soil nail wall was modeled, ; and a parametric study was performed.
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• Format:
  PDF
• Funding:
  0-6784
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31238/dot_31238_DS1.pdf
• File Type:
  [PDF - 520.20 KB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:f92019f6ae87880014754120cfa1776686a2f5ece4908cde7daeaa2e72c9d180