| Author | Shiwakoti, Dinesh Raj |
| Call Number | AIT Thesis no. GT-93-17 |
| Subject(s) | Tunneling
|
| Note | A thesis study submitted in partial fulfillment of the requirements for the degree of Masters of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GT-93-17 |
| Abstract | Effect of copy cutter on behaviour of shield at curved
alignment has been studied based on the assumption that
horizontal and vertical earth pressures acting on skin plate of
shield are functions of horizontal and vertical relative
displacements respectively.
Using the proposed model, influence of copy cutter to the
acting loads on shield have been made clear quantitatively.
Sensitivity of acting loads with change in radius of curve has
been investigated. Also the effects of tilt angle of shield,
depth of tunneling and strength of soil on shield behaviour have
been examined for tunneling in curved alignment.
From the research, it has been found that large magnitudes
of acting loads in sharp curves are caused by huge earth
pressures developed at inner side of curve. Earth pressure at
skin plate has been found to be maximum near the centre of the
shield cross-section along spring line of inner side of curve. It
has been shown that optimum values of copy cutter parameters
(length, range and location) exist. Largest reduction in acting
loads is achieved if copy cutter is located symmetrically along
spring line of inner curve located at 90 degree from the i nvert.
Acting loads go on decreasing with increase in range of copy
cutter but rate of decrease of acting loads reduces with increase
in range from that line. For copy cutter length of first few cm,
acting loads reduce sharply as a result of release in huge
pressure generated by skin plate pressing the ground. With
further increase in length of copy cutter, rate of reduction of
acting loads goes on decreasing and ultimately becomes constant.
It is has been demonstrated that optimum value of t ilt angle
exists which depends on construction conditions. In curved
alignment when shield is tilted, pattern of earth pressure at
skin plate reverses across shield cross-section. In this reversal
process, there lies a value of tilt angle for which acting loads
are minimum. |
| Year | 1993 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ;|vno. GT-93-17 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical and Transportation Engineering (GT) |
| Chairperson(s) | Sugimoto, Mitsutaka;Noppadol Phien-wej; |
| Examination Committee(s) | Bergado, Dennes T. ; |
| Scholarship Donor(s) | Government of Austria; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology |