VOL XI Issue 2
There are two major components in a soil grouting operation. The first step is the design of a site-specific grouting programme. The second step is the execution of that programme – this includes on-site monitoring and assessment of the operation in real-time. If these tasks are undertaken with state-of-the-art engineering methods, then the best achievable results will be predictably accomplished. Two recent developments are discussed in this paper; first, an in situ soil injection simulator (ISIS) developed for use during the design phase of a soil grouting programme; secondly, a computer aided grouting evaluation system (CAGES) developed for use during the execution phase of a soil or rock grouting programme.
The in situ soil injection simulator (ISIS) was developed to assist during the design phase of soil grouting programmes by improving on the present methods of determining and predicting the injectability limits of a given grout into a specific soil. The ISIS test cell was constructed with dimensions large enough to reduce the effect of “boundary conditions” that distort the results of typical injectability tests. The soil in question is reconstructed by matching the soil gradation (sieve curves), silt content, moisture content, overburden pressure, density, etc that exist in the field. These reconstructed soils are injected with different grout types and/or formulations to determine the injectability, lateral grout spread, residual permeability (both horizontally and vertically), and grouted soil strengths for each grout type. Alternatively, different soil layers can be constructed to resemble a variety of conditions to test the performance of the various grouts in different field conditions. This type of laboratory test can be instrumental in determining the type of grouts and spacing of the grout holes and for predicting the characteristics of the grouted soils. Without the ISIS these parameters are often determined by applying theories, mathematical models and ‘rules of thumb’ with variable degrees of success.
A computer aided grouting evaluation system (CAGES) has been developed to allow for rigorous real-time monitoring, analysis and assessment of grouting operations. CAGES is a commercially available software/hardware package that permits practitioners to modernise to higher standards, by improving the method in which their grouting operations are monitored and evaluated. CAGES not only collects, displays and stores relevant grouting data but, in addition, these data are analysed in real-time. CAGES then displays the raw grouting data, as well as calculated parameters, in an easy to interpret format so decisions pertaining to the grouting operation can be based on accurate information. CAGES can be configured for the simultaneous monitoring and analysis of up to eight holes for tight control of multiple-hole grouting programmes.
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