<p><p><strong>Reference(s):</strong></p><p><em>Baker et al. (1983)<br>Karol (2003)<br>Waller et al. (2003)</em></p><p><strong>Method Summary</strong></p><p>The Pressuremeter Test (PMT) procedure is described in ASTM D4719-07. PMT is used to obtain the stress-strain response of the soil in-situ. A PMT modulus and a limit pressure value are obtained from this test. Preparation for the test starts with drilling a cavity or a bore hole to insert the PMT probe to the desired depth. Sometimes the PMT probe is driven into place within a casing. The PMT equipment consists of an inflatable cylindrical probe. Test is performed by inserting the device into the borehole and expanding in the probe while measuring the changes in volume and pressure in the probe. The probe can be inflated under equal pressure increments or equal volume increments and the test is terminated when yielding in the soil becomes disproportionately large. A conventional limit pressure is estimated from the last few readings of the test and a PMT modulus value is calculated from the pressure-volume changes read during the test. It is important to insert the probe in a borehole with a diameter close to that of the probe.</p><p>The appropriate procedure for preparing the cavity should be selected based on the availability of tools and the need to minimize soil disturbance. The results of this test are dependent on the degree of disturbance occurred during drilling of a bore hole and insertion of the PMT probe. Disturbance cannot be completely avoided but should be minimized, and the interpretation of the test results should include consideration of such conditions during drilling. Knowledge of the type of soil is necessary for assessment of (a) the method of boring or probe placement, or both, (b) the interpretation of the test data, (c) the reasonableness of the test results.</p><p>This method can be difficult to perform sometimes as it needs a clean smooth sided borehole. Often the strength of the grouted soil is greater than the capacity of the pressuremeter.</p><p><strong>Accuracy and Precision</strong></p><p>ASTM D4719 states that the single most important factor in the successful completion of the test is the preparation of a good hole. This can be very difficult in soft clays and very loose sands. The precision of the test method is not presented in ASTM D4719 due to the nature of the test method. The standard also indicates that the accuracy of the PMT results cannot be determined as no accepted reference value is available. PMT is generally considered reliable in geotechnical engineering practice.</p><p><strong> </strong><strong>Adequacy of Coverage</strong></p><p>Sufficient evaluation requires many tests. The number of tests depends on the variability in subsurface conditions.</p><p><strong>Implementation Requirements</strong></p><p>This method is not always feasible due to ground conditions. Experience and special equipment are necessary.</p><p><strong>General Comments</strong></p><p>The borehole pressuremeter can be an effective QA tool under proper conditions. Testing sandy soils can make it difficult to produce a clean smooth borehole.</p></p>