Batter pile is used to find a more effective way to stabilize the slope. Thus, these two questions “where is the optimal location of batter piles on earth slopes?” and “which inclination angle is most beneficial for pile in earth slopes?” arise. The numerical simulation was conducted to investigate the performance of slope reinforced by batter pile. The surcharge loading, inclination angle and pile location were varied while keeping geometry of the slope and the soil property constant. The surcharge loading was applied on the slope crest by steps. The inclination angle varied from 0° to 20°. The pile was placed at middle-down (MD), middle (MI), middle-upper (MU) and upper (UP) part of slope, respectively. A finite length of batter pile (10 m) was adopted, and the pile toe was free. Four series of numerical models were proceeded to search the optimum location and inclination angle for pile, one that provided maximum lateral resistance. By analyzing the slope deformation and pile bending moment, the effects of position and inclination angle of pile were determined. The following conclusions could be drawn: (1) The surcharge loading on the slope crest will influence the deformation of slope remarkably. Both the lateral displacement and settlement increases simultaneously with the raise of loading. (2) The lateral displacement and settlement of slope vary as the pile location moves from the crest to the toe. The slope of UP condition has the the minimum lateral displacement, following by MI, MD and MU condition. The ranking of settlement is same with the lateral displacement. That is to say, the UP condition is the best location for piled slope, followed by MI condition. (3) The batter pile is beneficial for slope engineering, which can not only reduce the deformation of slope, but also decrease the bending moment exerted on pile shaft. The inclination angle should be in a reasonable range, a relatively small inclination angle could not fully utilize the potential capacity of batter pile, while exaggerated inclination degree is not befitting for construction. The inclination angle of 15° is an optimal choice for batter pile in slope. (4) The inclination angle has mutual effect with the pile location, they should be considered synchronously. For comprehensive consideration, UP 10°, UP 15°, MI 15° and MI 20° are preferred options for the piled earth slope when subjected to surcharge loading.

To evaluate the performance of dual-row batter pile wall (DRBPW) in deep excavations, a three-dimensional numerical model was established. The plastic hardening (PH) constitutive model in FLAC^3D was adopted, considering the hardening property of the soil. A series of parametric study was conducted to investigate the effect of different factors. By analyzing the maximum lateral displacement, the pile shaft deflection and bending moment of both the leading and trailing row, the effect of inclination angle, pile diameter, penetration depth, and row spacing on the behavior of DRBPW was determined. The following conclusions could be drawn: (1) The bearing capacity of DRBPW is quite larger than that of the dual-row vertical pile wall (DRVPW). With the increase of inclination angle, a substantial reduction of lateral displacement could be observed. However, the beneficial role of batter pile is almost negligible when the inclination angle is not larger than 5°. The recommended inclination degree of the batter pile is 10° to 15°. (2) The maximum displacement of the leading and trailing rows lies at a distance below the pile cap, while the maximum bending moment is located at a small distance below the dredging line. The maximum bending moment of the leading pile is approximately twice that of the trailing one, thereby indicating that the leading pile bear more lateral earth pressure than the trailing pile. (3) The pile diameter, penetration depth and row spacing should be maintained in a suitable range; otherwise, the DRBPW may fail earlier than expected. The slender ratios is recommend to be set not larger than 30. The penetration ratio should not be less than 0.22. The optimal row spacing for the DRBPW is four times the diameter.

With the increasing excavation depth of foundation pits, the traditional cantilever vertical pile wall cannot meet the requirements of ground settlement and lateral deflection, and excess deformations would cause not only retaining system failures but also damage of adjoining structures. Thus, a batter pile wall was employed, but its behavior has not been fully demonstrated. To evaluate the performance of the batter pile wall, the laboratory model test was conducted on the basis of scaling law, and the numerical simulation was employed for the validation of experimental results. The results indicated the following conclusions: (1) The bearing capacity of batter pile wall is quite larger than that of the vertical one. The inclination degree should be in an appropriate range, otherwise, the efficiency of batter pile may decrease or leading to occupation of the precious excavation space. The recommended inclination angle is 9° to 15°. (2) With the increase in inclination angle, the pile shaft deflection, ground settlement and bending moment decrease significantly. The influencing distance of excavation is approximately 1.2 times of the dredging depth. (3) The cross section size, penetration depth and shear strength of soil would influence the response of batter pile wall, thus a careful optimazition process is necessary. For insurance purposes, the slender ratios are recommended to be set less than 40 and the penetration ratio is suggested to be larger than 0.4 to minimize the lateral deflection.

The construction of modern city consists of many underground facilities, and one major concern is how to construct them safely and efficiently. Thus, the excavation-induced pile response needs to be evaluated. Dual-row batter pile wall (DRBPW) exhibits better performance than traditional dual-row vertical pile wall (DRVPW) in foundation pit engineering. However, the study of single pile subjected to excavation-induced soil movement behind DRVPW is rather limited, needless to say that of the DRBPW. An explicit finite difference method (FDM) was utilized to obtain the responses of isolated floating single pile (IFSP) near deep excavations braced by DRBPW. The responses of IFSP in the vicinity of foundation pit reinforced by DRBPW were compared to that of the DRVPW. The pile length, distance of pile from wall, excavation depth, working load, and Young’s modulus of pile were considered in the parametric study. The conclusions were as follows: (1) The DRBPW can minimize the influence on the existing pile; thus, the induced lateral displacement and bending moment of pile retained by DRBPW are smaller than that of DRVPW. (2) The excavation depth, pile location, and pile length have significant influence on the responses of IFSP adjacent excavation, while the working load and Young’s modulus of pile have diminutive influence. (3) The influence zone induced by excavation can be divided into two areas. The primary influence zone is the severely affected area where the induced deformation and bending moment are remarkable. The secondary influence zone is the moderately affected area where the induced deformation and bending moment are mild. The primary influence zone is within twice of the excavation depth. The secondary influence zone is 2.0–3.0 times that of the excavation depth. (4) The pile toe of IFSP has considerable lateral displacement during excavation, and attentions should be paid to the whole pile shaft during construction.

For the consideration of required elevation, pile shafts are partially buried in the soil stratum and partially exposed above the ground surface, known as high-rise pile group (HRPG). The HRPG is extensively used in the construction of infrastructures and is usually adjacent the slope. It is frequently subjected to high lateral loads from the superstructure, leading to considerable displacement and bending moment. To alleviate the deformation and internal force of HRPG, a batter pile is employed, forming the high-rise batter pile group (HRBPG). A numerical simulation is conducted to observe the response of HRPG foundation subjected to downwards lateral load adjacent slope. The effects of slope angle, cap elevation, and lateral loading magnitude are determined. Results of HRBPG are compared with traditional high-rise vertical pile group (HRVPG). Conclusions can be drawn as follows. (1) The slope has significant effect on the displacement and bending moment of HRPG, so it should be considered in the design process. The displacement and bending moment of pile shaft increase gradually with the slope angle (0°–30°) and then they have a sharp growth (45°–60°). (2) With the rise of cap elevation, the displacement increases dramatically, whereas the bending moment rises and then falls. The displacement is highly sensitive under lateral loading with a high cap elevation; the higher the elevation is, the greater the displacement will be. Special attention should be paid when a high pile cap is adopted under large lateral loading. The displacement and bending moment of HRBPG are considerably smaller than those of HRVPG at a high pile cap elevation. (3) The displacement and bending moment are relatively small when a diminutive lateral loading is performed; however, they have a sharp growth under large lateral loading. The larger the load is, the greater the bending moment and displacement will be. (4) The displacement of the leading pile is slightly larger than that of the trailing pile, whereas the bending moment of the rear pile is larger than that of the leading pile. The pile shaft displacement above the ground surface is considerably larger than that below. The maximum bending moment occurs at the pile head, and the pile toe has minuscule bending moment. (5) The use of batter pile is beneficial for reducing the displacement and bending moment, whereas the slope and lateral loading are detrimental.