Prediction of Behaviour of Tunnels in Squeezing Ground

An integrated approach for the pathology assessment and protection of underground monuments in seismic regions. Application on some greek-roman monuments in Alexandria Egypt

“…The second, which is probably the most significant one, is the degradation of deformability and strength characteristics of rocks with time (Aydan and Nawrocki, 1997;Sato et al, 1995). Aydan et al (1992Aydan et al ( , 1993 proposed a method to predict the squeezing potential of rocks during excavations.…”

Prediction Method of Tunnel Deformation Using Time-dependent Ground Deterioration Model

“…It is possible to model almost all deformation patterns with these three lines/curves other than exceptionally abnormal deformation. Figure 3 shows the strength reduction curve when c 0 is set at 0.56 MPa (with the unconfined strength assumed as qu = 2.0 MPa according to formulae in published literature [3,4]) and A is a value to make cohesion c 0 /2 at a point 30 years after the start of deterioration. The authors used these strength reduction curves for analysis on a trial basis.…”

“…The authors modeled the ground as a material that satisfies the Mohr-Coulomb yield criterion, and set the initial unconfined strength at 2 MPa (by assuming soft rock from the Neogene period) and the coefficient of lateral pressure at 0.43 (by assuming a state of homogeneous and isotropic plane strain at a Poisson's ratio of 0.3). After determining the values of cohesion c and elastic modulus E of the ground by referring to published literature [3,4] that proposes a static correlation formula for the unconfined strength and other material property values, the authors expressed the deterioration of the ground by reducing the value of cohesion c, one of the shearing strength constants of the ground. Table 2 lists data on the lining used for analysis.…”

Uniaxial and Triaxial Creep Performance of Calcarenitic and Sandy Oolitic Limestone Formations for Stability Analysis of Roman Rock-Cut Tombs in Alexandria, Egypt

“…Some of the main concerns related to the stability of underground structures in soft rocks include the effects of potential land disturbances through the method of drilling and reallocation of pressures at the site surrounding the excavations [30][31][32][33][34][35]. Each of these factors relates to the initiation and spread of fragile fractures and the extent of the troubled drilling area (EDZ), which can adversely affect the stability of the drilling boundaries and can increase the permeability of host rocks to the near field.…”