粘土水泥浆在井筒地面预注浆中的应用

粘土水泥浆注浆材料是一种新型的较理想的注浆材料，在平顶山十三矿主，副井井筒地面预注浆中应用了粘土水泥浆注浆法，取得了良好效果，并积累了一定的经验。     

An Approximate Method to Determine Lateral Force on Piles or Piers Installed to Support a Structure through Sliding Soil Mass

Piles and drilled shafts are commonly used to stabilize potentially unstable natural and engineered slopes. Estimation of lateral pressures on piles or shafts used to stabilize potentially unstable sites continues to be a fundamental problem in geotechnical engineering. Several methods are available to estimate the lateral force on piles or drilled shafts used to stabilize a site. An approximate procedure to estimate the lateral force on drilled shafts supporting structures, i.e., installed at relatively large spacings on a potentially unstable site with a fixed slip surface is proposed, which is based on a widely referred theory of plastic deformation. Lateral pressures estimated using the method proposed show good agreement with a more rigorous method, which in turn has been reported to provide results close to field measurements. An approximate procedure to estimate a limiting (maximum) value of lateral pressure on shafts or piles when they are installed at close spacings is also proposed. Although, the limiting pressures estimated using the approximate procedure are in agreement with the pressures calculated using more rigorous method, verification of both methods with field measurements is recommended.     

Current and future UK practice for the permanent support of shaft excavations

Summary Mining development work in the UK is primarily concerned with the coal industry. Sedimentary rocks of the sandstone, marl and limestone types and coal measures are the predominant strata through which new shafts or existing shaft deepenings penetrate. The paper discusses hydrogeological information, the loadings imposed on shaft linings in such strata and outlines design philosophy. Design formulae are quoted and design practice is reviewed with reference to the current UK Codes of Practice for concrete construction.Included in the overall shaft lining design concept should be a consideration of the installation factors. Construction aspects and the influence of strata water control measures are therefore discussed in relation to recent advances using high-strength concrete and water pressure relief. New concepts in shaft lining design are also proposed and commented upon. Finally, the significant features of shaft lining design and construction are emphasized.     

Limit equilibrium based design approach for slope stabilization using multiple rows of drilled shafts

In this paper, a limiting equilibrium based methodology, incorporating the method of slices and arching effects of the drilled shafts, is developed for optimizing the use of multiple rows of drilled shafts. This proposed method is focusing on the number of rows, the location of each row, the dimension and spacing of the drilled shafts. Three design criteria are used for optimization: target global factor of safety, the constructability and service limit. A PC-based program called M-UASLOPE has been coded to allow for handling of complex slope geometry, soil profile, and ground water conditions. A design example is presented to illustrate the application of the M-UASLOPE program in the optimized design of multiple rows of drilled shafts for stabilizing the example slope.     

Shaft and base resistance of non-displacement piles in sand

This paper presents the results of three-dimensional, finite element analyses performed with an advanced, two-surface-plasticity, constitutive sand model to investigate the response of non-displacement piles to axial loading. The analysis domain is carefully meshed such that the formation and evolution of shear bands next to the pile shaft and near the pile base can be properly captured. Analyses considering various soil profiles and pile geometries show that the mobilized lateral earth pressure coefficient K along the pile shaft increases with increasing relative density and decreasing initial confining stress. The ultimate unit base resistance is independent of pile diameter, increasing with increasing relative density and increasing initial confining stress at the pile base. Based on the analysis results, design equations are proposed to estimate the limit shaft resistance and ultimate base resistance of non-displacement piles in sandy soil. In proposing these relationships, the pile slenderness ratio is considered. The effect of layer proximity to the base of the pile or pile base embedment in a layer is also considered.