Abstract
Double-row steel pipe piles have been widely used in retaining and protection of foundation excavation because of the advantages of high bearing capacity, high flexural rigidity, fast construction speed, and so on. This study presents a field test to assess the feasibility of strain gauges in monitoring the strain of double-row steel pipe piles during foundation excavation. Two steel pipe piles were instrumented with strain gauges and then installed into the drilling holes. The installation method of strain gauges is introduced first. Then, the bending moment of the test piles during the foundation excavation was analyzed. The field test results indicate that the survival rate of strain gauges was 100%, and the monitoring method used in the test was feasible to measure the bending moment of double-row steel pipe piles. Moreover, with the increase in foundation excavation depth, the bending moment of the test piles all increased, and the bending moment of the inner pile was obviously higher than that of the outer pile. The bending moment distribution of the whole support system accords with the conventional pile-anchor mode. The test results can provide reference and basis for the design and construction of double-row steel pipe piles.
Highlights
With the rapid development of high-rise buildings and underground structures, the scale of underground projects was increasing, and the design and construction of deep pit support was becoming more and more important [1,2,3]
E double-row steel pipe pile is a kind of spatial composite support structure, which is composed of two rows of reinforced steel pipe piles and rigid connected top beams [8]. e bearing capacity of this support structure is good, and the deformation of the foundation pit can be controlled well [9, 10]
Shi and Gong. [15] used finite element software to simulate the excavation process of the deep foundation pit supported by double-row piles and studied the mechanical characteristics of double-row piles
Summary
With the rapid development of high-rise buildings and underground structures, the scale of underground projects was increasing, and the design and construction of deep pit support was becoming more and more important [1,2,3]. The double-row steel pipe pile has a good applicability for foundation pit support engineering [11]. In order to improve the bearing capacity, optimize the design, and guide the construction of this support structure, many scholars have studied the mechanical characteristics of the steel pipe pile. Bai et al [13] established a calculation model of double-row pile support structure in the deep foundation pit considering the spatial effect and analyzed the influence of the top beam on the bearing capacity of double-row pile structure. [15] used finite element software to simulate the excavation process of the deep foundation pit supported by double-row piles and studied the mechanical characteristics of double-row piles.
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