## 3 Results and Discussion
### Analysis of Horizontal Static Load Test of Single Pile
#### 3.2.2 Analysis and Judgment of Test Data  
The horizontal ultimate bearing capacity of a single pile shall be comprehensively analyzed and determined according to the following methods: (1) take the horizontal load value corresponding to the starting point of an obvious steep drop of \(H\)-\(Y_{0}\) curve; (2) take the horizontal load value of the previous level with obvious bending at the tail of \(Y_{0}\)-l\(g\)t curve; (3) take the horizontal load value corresponding to the second inflection point on \(H\)-\(\Delta Y_{0}/\Delta H\) curve or lg\(H\)-lg\(Y_{0}\) curve; and (4) the load value of the previous level of pile shaft breaking. After that, according to the specification requirements, the characteristic value of the horizontal bearing capacity of a single pile shall comply with the following provisions: (1) when the pile body is not allowed to crack or the reinforcement ratio of the cast-in-place pile body is less than 0.65%, and then 0.75 times of the horizontal critical load can be taken as the characteristic value of the horizontal bearing capacity of a single pile. (2) For reinforced concrete precast pile, the characteristic value of horizontal compressive bearing capacity of a single pile is 0.75 times the load corresponding to the horizontal displacement at the design elevation as the characteristic value of horizontal bearing capacity of the single pile, and the horizontal displacement shall be taken as follows: (1) 6 mm for buildings sensitive to horizontal displacement and (2) 10 mm for buildings insensitive to horizontal displacement. (3) The load corresponding to the horizontal allowable displacement required by the design is taken as the characteristic value of the horizontal bearing capacity of a single pile. According to the test results of the horizontal static load test of a single pile, the curves of horizontal load-displacement (\(H\)-\(Y_{0}\)) and displacement-time logarithm curve (\(Y_{0}\)-l\(g\)t) are drawn for the selected single pile No. 5, as shown in Figure 11.  
From Figure 11, when the test load is increased to 300 kN, the observation at this level lasts 120 min and the displacement is relatively stable, and the loading has reached the maximum test load value, so the loading is terminated. According to the technical requirements, the measured data are sorted and summarized, and the horizontal force-displacement (\(H\)-\(Y_{0}\)) curve and displacement-time logarithm curve (\(Y_{0}\)-l\(g\)t) curve are analyzed. The maximum loading value of the tested pile test is 300 kN, the cumulative total displacement of a force action point is 31.89 mm, there is no obvious steep drop section in the horizontal force-displacement (\(H\)-\(Y_{0}\)) curve, the detection result of horizontal critical load of the single pile is 300 kN, and the detection result of the characteristic value of horizontal bearing capacity of the single pile is 225 kN, which meets the design requirements. With the increase of horizontal load, the horizontal displacement also increases gradually, but due to the large pile diameter, the increase of horizontal displacement under each level of load is not very large. In the whole loading process, the horizontal displacement and horizontal load change in a nonlinear relationship. The measured results are related to many factors, such as the stiffness of the pile, the depth of the pile into the soil, the size and shape of the pile section, the size of the horizontal load and the engineering properties of the soil around the pile.