Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy load imposed by high-rise structures, due to the low settlement and high bearing capacity. In t...Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy load imposed by high-rise structures, due to the low settlement and high bearing capacity. In the optimum design of semi-deep foundations, prediction of the shaft bearing capacity, rs, of foundations socketed in rocks is thus critically important. In this study, the unconfined compressive strength(UCS), qu, has been applied in order to investigate the shaft bearing capacity. For this, a database of 106 full-scale load tests is compiled with UCS values of surrounding rocks, in which 34 tests with rock quality designation(RQD), and 5 tests with rock mass rating(RMR). The bearing rocks for semi-deep foundations include limestone, mudstone, siltstone, shale, granite, tuff, granodiorite, claystone, sandstone, phyllite, schist, and greywacke. Using the database, the applicability and accuracy of the existing empirical methods are evaluated and new relations are derived between the shaft bearing capacity and UCS based on the types of rocks. Moreover, a general equation in case of unknown rock types is proposed and it is verified by another set of data. Since rock-socketed shafts are supported by rock mass(not intact rock), a reduction factor for the compressive strength is suggested and verified in which the effect of discontinuities is considered using the modified UCS, qu(modified), based upon RMR and RQD in order to take into account the effect of the rock mass properties.展开更多
A new comprehensive set of data（n = 178） is compiled by adding a data set（n = 72） collected by Arioglu et al.（2007） to the data set（n = 106） presented in Rezazadeh and Eslami（2017）. Then, the compiled data s...A new comprehensive set of data（n = 178） is compiled by adding a data set（n = 72） collected by Arioglu et al.（2007） to the data set（n = 106） presented in Rezazadeh and Eslami（2017）. Then, the compiled data set is evaluated regardless of the variation in lithology/strength. The proposed empirical equation in this study comprises a wider range of uniaxial compressive strength（UCS）（0.15 MPa 〈 σ_（rc） 〈156 MPa） and various rock types. Rock mass cuttability index（RMCI） is correlated with shaft resistance（r_s） to predict the shaft resistance of rock-socketed piles. The prediction capacity of the RMCI versus r_s equation is also found to be in a fair good agreement with the presented data in Rezazadeh and Eslami（2017）. Since the RMCI is a promising parameter in the prediction of shaft resistance, the researchers in the rock-socketed pile design area should consider this parameter in the further investigations.展开更多
Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy loads imposed by high-rise buildings and special structures, due to the low settlement and high...Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy loads imposed by high-rise buildings and special structures, due to the low settlement and high bearing capacity. In this study, the unconfined compressive strength（UCS） and rock mass cuttability index（RMCI） have been applied to investigating the shaft bearing capacity. For this purpose, a comprehensive database of 178 full-scale load tests is compiled by adding a data set（n = 72）collected by Arioglu et al.（2007） to the data set（n = 106） presented in Rezazadeh and Eslami（2017）.Using the database, the applicability and accuracy of the existing empirical methods are evaluated and new relations are derived between the shaft bearing capacity and UCS/RMCI. Moreover, a general equation in case of unknown rock types is proposed and it is verified by another set of data（series 3 in Rezazadeh and Eslami（2017））. Since rock-socketed shafts are supported by rock mass（not intact rock）,a reduction factor for the compressive strength is suggested and verified in which the effect of discontinuities is considered using the modified UCS, based upon RMR and RQD to consider the effect of the rock mass properties.展开更多
文摘Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy load imposed by high-rise structures, due to the low settlement and high bearing capacity. In the optimum design of semi-deep foundations, prediction of the shaft bearing capacity, rs, of foundations socketed in rocks is thus critically important. In this study, the unconfined compressive strength(UCS), qu, has been applied in order to investigate the shaft bearing capacity. For this, a database of 106 full-scale load tests is compiled with UCS values of surrounding rocks, in which 34 tests with rock quality designation(RQD), and 5 tests with rock mass rating(RMR). The bearing rocks for semi-deep foundations include limestone, mudstone, siltstone, shale, granite, tuff, granodiorite, claystone, sandstone, phyllite, schist, and greywacke. Using the database, the applicability and accuracy of the existing empirical methods are evaluated and new relations are derived between the shaft bearing capacity and UCS based on the types of rocks. Moreover, a general equation in case of unknown rock types is proposed and it is verified by another set of data. Since rock-socketed shafts are supported by rock mass(not intact rock), a reduction factor for the compressive strength is suggested and verified in which the effect of discontinuities is considered using the modified UCS, qu(modified), based upon RMR and RQD in order to take into account the effect of the rock mass properties.
基金support of Yapi Merkezi Construction and Industry Inc.,Istanbul,Turkey
文摘A new comprehensive set of data（n = 178） is compiled by adding a data set（n = 72） collected by Arioglu et al.（2007） to the data set（n = 106） presented in Rezazadeh and Eslami（2017）. Then, the compiled data set is evaluated regardless of the variation in lithology/strength. The proposed empirical equation in this study comprises a wider range of uniaxial compressive strength（UCS）（0.15 MPa 〈 σ_（rc） 〈156 MPa） and various rock types. Rock mass cuttability index（RMCI） is correlated with shaft resistance（r_s） to predict the shaft resistance of rock-socketed piles. The prediction capacity of the RMCI versus r_s equation is also found to be in a fair good agreement with the presented data in Rezazadeh and Eslami（2017）. Since the RMCI is a promising parameter in the prediction of shaft resistance, the researchers in the rock-socketed pile design area should consider this parameter in the further investigations.
文摘Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy loads imposed by high-rise buildings and special structures, due to the low settlement and high bearing capacity. In this study, the unconfined compressive strength（UCS） and rock mass cuttability index（RMCI） have been applied to investigating the shaft bearing capacity. For this purpose, a comprehensive database of 178 full-scale load tests is compiled by adding a data set（n = 72）collected by Arioglu et al.（2007） to the data set（n = 106） presented in Rezazadeh and Eslami（2017）.Using the database, the applicability and accuracy of the existing empirical methods are evaluated and new relations are derived between the shaft bearing capacity and UCS/RMCI. Moreover, a general equation in case of unknown rock types is proposed and it is verified by another set of data（series 3 in Rezazadeh and Eslami（2017））. Since rock-socketed shafts are supported by rock mass（not intact rock）,a reduction factor for the compressive strength is suggested and verified in which the effect of discontinuities is considered using the modified UCS, based upon RMR and RQD to consider the effect of the rock mass properties.
