The SMR geomechanics classification system (adaptation of RMR for slopes) is reviewed with data from 87 actual slopes in Valencia. In a research project, SMR has been applied by a GIS system, as a method to forecast stability problems in future road construction.

On revient sur la classification geomechanique SMR (une adaptation du RMR pour talus et pentes) avec les dates de 87 talus existant autour de Valencia. Dans le cadre d'un projet de recherche SMR a ete appliquee, avec un système GIS, comme methode de prevision de stabilite problèmes dans la construction de futures routes. Une methodologie pour l'application du GIS a ete developpe.

Das Geomechanische Einteilungssystem SMR (eine Anpassung des RMR an Böschungen) wird an Hand der Daten von 87 Böschungen im Gebiet von Valencia ueberdacht. In einem Forschungsprojekt wurde das SMR in einem Geographischen Informationssystem (GIS) als Methode zur Vorhersage von Stabilitatsproblemen bei zukuenftigen Straßenbauprojekten eingesetzt. Das Ergebnis dieser Arbeit ist die Entwicklung einer Methodologie fuer die GIS- Anwendung


RMR "Rock Mass Rating" geomechanics classification (also called CSIR) was introduced and developed by BIENIAWSKI (1973, 1984, 1989) deal extensively with RMR (and other geomechanics classification systems). A good recent reference to RMR application to tunnels in BIENIAWSKI (1993). RMR has become a standard for use in tunnels and many professionals apply it to describe any rock mass. ORR (1996) has given a good overview of the RMR use in slopes. LAUBSCHER (1976), HALL (1985) and ORR (1992) proposed different relationships between RMR value and limit angle for slopes. STEFFEN (1978) classified 35 slopes and concluded that "results had a statistical trend". ROBERTSON (1988) established that when RMR > 40 the slope stability is governed both by orientation and shear strength of discontinuities whereas for RMR < 30 the failure develops across the rock mass.

In the 1976 version, the "rating adjustments for discontinuity orientation" for slopes were: very favourable 0, favourable - 5, fair -25, unfavourable -50, very unfavourable -50, very unfavourable -60. No guidelines have been published for the definition of each class. A mistake in this value can supersede by far any careful evaluation of the rock mass, and classification work becomes both difficult and arbitrary. ROMANA (1985, 1993, 1995) proposed a new addenda to RMR concept, specially suited to slopes. BIENIAWSKI (1989) has endorsed the method.

SMR Classification system

The "Slope Mass Rating" (SMR) is obtained from RMR by adding a factorial adjustment factor depending on the relative orientation of joints and slope and another adjustment factor depending on the method of excavation.

(Equation in full paper)

The RMRB (see Table 1) is computed according Bieniawski´s1979 proposal, adding rating values for five parameters:

  • strength of intact rock;

  • RQD;

  • spacing of discontinuities;

  • condition of discontinuities; and

  • water inflow through discontinuities and/or pore pressure ratio.

The adjustment rating for joints (see Table 2) is the product of three factors as follows:

  • F1 depends on parallelism between joints and slope face strike.

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