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Abstract The soil arch effect of the open cut tunnel and the variations of the earth pressure with the heights of the filled soils under the different load reduction schemes were studied with the model tests of reduced scales. The experimental results showed that the earth pressures on the top of open cut tunnel increased nonlinearly and the soil arch effect occurred when the filled height was up to a certain level. The soil arch effect was not stable and the soil stresses measured at the crest of the tunnel were smaller than the calculated ones. A single layer of geogrid was thus proposed to be placed above the tunnel and a corresponding method of calculation of the earth pressures at the top of the geogrid，under the geogrid and on the crest of the open cut tunnel was presented on the basis of Rankine?s theory of earth pressure. In addition，an expression of earth pressures for multiple layers of geogrid was also derived. The field experiment of an open cut tunnel demonstrated that the load reduction by geogrid was effective and the calculation method was appropriate.
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Received: 09 July 2013
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2014, Vol. 33 
