排序方式: 共有7条查询结果,搜索用时 15 毫秒
1
1.
Site investigation and evaluation of properties of soil or rock are important aspects of geotechnical design. Determination of the ground stiffness is one of the important parameters in geotechnical engineering. Since the measurement of shear modulus is very sensitive to soil disturbance, especially for sand, determination of the stiffness of soil in the field is more reliable than in laboratory tests on sampled specimens. Measurement of shear modulus is one of the most common applications of self-boring pressuremeter testing. As an in situ device, the pressuremeter provides a unique method for assessing directly the in situ shear modulus of a soil. This paper describes a laboratory study of silica sand stiffness, which varies with stress level and strain amplitude. The results show that the elastic shear modulus value is mainly dependent on the value of the mean effective stress and relative density. 相似文献
2.
根据建筑实际荷载与变形的观测资料及地基情况,可计算碎石类压实填土人工地基的变形模量E0值。试验与计算结果对比分析表明,采用重型动力触探试验及旁压试验来确定这类人工地基的变形模量E0值是安全的。指出这类人工地基承载力标准值,可由其变形模量及拟建建筑物允许沉降量来确定。 相似文献
3.
The extreme net pressure resulting from an expansion in a cylindrical or spherical cavity within a limitless medium is studied.
Performing the static and kinematic approaches of yield design theory, analytical solutions of the extreme net pressure are
established for cohesive–frictional as well as for purely cohesive medium. In the case of a cylindrical cavity, the identification
between the analytical extreme net pressure and limit net pressure leads to the prediction of shear strength characteristics
of soil. As useful result, in soil mechanics, the assessment of correlations using pressuremeter data has been discussed.
Also, some assumptions for designing foundations, from pressuremeter data, have been highlighted. 相似文献
4.
5.
6.
Ali Bouafia 《Geotechnical and Geological Engineering》2007,25(3):283-301
Lateral load-deflection behaviour of single piles is often analysed in practice on the basis of methods of load-transfer P–Y curves. The paper is aimed at presenting the results of the interpretation of five full-scale horizontal loading tests of
single instrumented piles in two sandy soils, in order to define the parameters of P–Y curves, namely the initial lateral reaction modulus and the lateral soil resistance, in correlation with the pressuremeter
test parameters. P–Y curve parameters were found varying as a power of lateral pile/soil stiffness, on the basis of which hyperbolic P–Y curves in sand were proposed. The predictive capabilities of the proposed P–Y curves were assessed by predicting the soil/pile response in full-scale tests as well as in centrifuge tests and a very good
agreement was found between the computed deflections and bending moments, and the measured ones. Small-sized database of full-scale
pile loading tests in sand was built and a comparative study of some commonly used P–Y curve methods was undertaken. Moreover, it was shown that the load-deflection curves of these test piles may be normalised
in a practical form for an approximate evaluation of pile deflection in a preliminary stage of pile design. At last, a parametric
study undertaken on the basis of the proposed P–Y curves showed the significant influence of the lateral pile/soil stiffness on the non-linear load-deflection response. 相似文献
7.
Deformability of rock masses influencing their behavior is an important geomechanical property for the design of rock structures. Due to the difficulties in determining the deformability of jointed rock masses at the laboratory-scale, various in-situ test methods such as pressuremeter, dilatometer, plate loading tests etc. have been developed. Although these techniques are currently the best and direct methods, they are time-consuming and expensive, and present operational difficulties. In addition, the influence of the test volume on deformation modulus depending on the method employed is also important. For these reasons empirical equations to indirectly estimate the deformation modulus have also been recommended by several investigators as an alternative approach. In this study; the geomechanical quality of weak, heavily jointed, sheared and/or blocky greywacke rock masses, on which very concentrated civil works are continuing at the southern and southwestern parts of Ankara (Turkey), was assessed. The deformation modulus was determined by pressuremeter tests, the possible effects of variables on the derived deformation modulus from the pressuremeter test were evaluated by numerical methods, and the comparisons between the deformation modulus of the greywackes obtained from the pressuremeter tests and their geomechanical quality (GSI and RMR) were made. Numerical simulations revealed that the presence of a disturbed annulus around the borehole causes underestimation of the deformation modulus, while the effect of length to diameter ratio of the pressuremeter probe on the deformation modulus is minor. Based on the geo-engineering characterization assessments, mainly two greywacke rock masses with different geomechanical qualities were identified. Geotechnical quality of one of these rock masses was verified by the back analysis of two slope failures. The empirical equations to indirectly estimate the deformation modulus of the greywackes using their GSI and RMR values yielded high coefficients of correlation. 相似文献
1