爆炸荷载作用下三相饱和钙质砂的液化特性

doi:10.12382/bgxb.2023.0739

摘要/Abstract

摘要：

由于钙质砂内部含有大量孔隙,钙质砂通常处于三相饱和状态,其液化特性与完全饱和状态有明显不同。采用自主研制的装置开展三相饱和钙质砂的大尺寸爆炸模型试验,分析三相饱和状态下钙质砂的爆炸液化特性,建立三相饱和钙质砂的超孔隙水压力的长期消散模型。针对三相饱和钙质砂自身特点建立其动力液化模型,通过对爆炸试验进行数值模拟验证模型的可靠性。有关研究结果为沿海岛屿的爆炸灾后地基稳定性分析及安全防护设施建设提供了重要参考。

关键词: 钙质砂, 爆炸荷载, 三相饱和, 液化

Abstract:

Due to a large number of pores inside the calcareous sand, the calcareous sand is usually in a three-phase saturated state, and its liquefaction characteristics are significantly different from the fully saturated state. The large-scale explosion model of three-phase saturated calcareous sand is test out by using a self-developed device. The explosion liquefaction characteristics of calcareous sand under three-phase saturation is analyzed. A long-term dissipation model of excess pore water pressure of three-phase saturated calcareous sand is established. A dynamic liquefaction model is established for the characteristics of three-phase saturated calcareous sand, and the reliability of the model is verified by numerical simulation of explosion experiment. The research results can provide reference for the analysis of foundation stability and the construction of safety protection facilities after the explosion disaster in coastal islands.

Key words: calcareous sand, explosive loading, three-phase saturated state, liquefaction

中图分类号:

黎晓冬, 王亚松, 邱艳宇, 王明洋, 岳松林, 王建平, 邓树新. 爆炸荷载作用下三相饱和钙质砂的液化特性[J]. 兵工学报, 2023, 44(S1): 170-179.

LI Xiaodong, WANG Yasong, QIU Yanyu, WANG Mingyang, YUE Songlin, WANG Jianping, DENG Shuxin. Liquefaction Characteristics of Three-phase Saturated Calcareous Sand under Explosive Loading[J]. Acta Armamentarii, 2023, 44(S1): 170-179.

图/表 19

图1 试验装置

Fig.1 Explosion experiment device

表1 试样的各项物理指标

Table 1 Physical indexes of samples

最小干密度/ (g·cm^-3)	最大干密度/ (g·cm^-3)	比重 G_s	天然孔隙比 e	内摩擦角 φ/(°)	压缩模量 E_s/MPa	剪切波速 v_s/(m·s^-1)
1.129	1.51	2.846	0.55	35.41	21.679	269.618

图2 试样颗分曲线

Fig.2 Grain size distributions of samples

表2 试验方案

Table 2 Experiment program

试验编号	起爆方式	炸药当量/g	埋深/cm
S1	单点	8	95
S2	单点	27	92
S3	单点	64	100
M1	两点100ms延迟	8, 16	80, 77
M2	三点100ms延迟	27, 27, 27	100, 100, 100

图3 传感器分布垂直剖面图

Fig.3 Vertical profile of sensor distribution

图4 单次爆炸荷载作用下三相饱和钙质砂的典型压力时程曲线

Fig.4 Typical pressure-time curve of three-phase saturated calcareous sand under single explosion loading

图5 试验S1、S3中测点B1处的超孔隙水压力变化

Fig.5 Variation curves of excess pore water pressure at measurin point B1 in Tests S1 and S3

图6 试验S2和M2中测点B1处的超孔隙水压力变化

Fig.6 Variation curves of excess pore water pressure at measuring point B1 in Tests S2 and M2

图7 峰值超孔压vs比例爆距

Fig.7 Relationship between the peak excess pore water pressure and the scaled distance

图8 峰值压力与比例爆距的关系

Fig.8 Relationship between the peak pressure and the scaled distancez

表3 饱和砂土中峰值超孔压的经验方程

Table 3 Empirical equations of peak excess pore pressures of different saturated sands

经验关系	砂土类型
u_pk=50093[m/kg^1/3]^-2.38	冲积河砂^[27]
u_pk=143000[m/kg^1/3]^-2.34	尾矿砂^[27]
u_pk=47900[m/kg^1/3]^-1.45,D_r=48% u_pk=47400[m/kg^1/3]^-1.45,D_r=74% u_pk=47200[m/kg^1/3]^-1.45,D_r=99%	混凝土骨料^[28]

图9 孔压比vs比例爆距

Fig.9 Relationship between the pore pressure ratio and the scaled distance z

图10 试验S2、S3和M2中测点B1、B2及B4处超孔压的长时消散

Fig.10 Long-term dissipation of excess pore pressures at measuring points B1, B2 and B4 in Tests S2, S3 and M2

图11 超孔隙水压消散的拟合结果

Fig.11 Fitting results of excess pore water pressure dissipation

表4 超孔隙水压消散的拟合参数

Table 4 Fitting parameters of excess pore water pressure dissipation

试验编号	u_e0/kPa	u_r/kPa	α	R²
S2-B₁	2.45	1.93	0.022	0.998
S3-B₁	2.61	1.30	0.071	0.999
M2-B₁	2.65	1.37	0.045	0.996
S2-B₂	2.29	1.94	0.020	0.998
S3-B₂	2.45	1.28	0.072	0.999
M2-B₂	2.43	1.28	0.046	0.996
S2-B₄	2.16	1.76	0.026	0.998
S3-B₄	2.03	1.14	0.091	0.999
M2-B₄	2.17	0.99	0.042	0.998

表5 各组分初始状态条件

Table 5 Initial state conditions of each component of sample

组分	含量/%	初始压力	初始密度	声速
空气	α₁	p_a	ρ₁₀	c₁₀
水	α₂	p_w	ρ₂₀	c₂₀
固体颗粒	α₃	p_s	ρ₃₀	c₃₀

图12 三相饱和钙质砂数值计算几何模型

Fig.12 Numerical calculation geometric model of three-phase saturated calcareous sand

表6 钙质砂的主要参数

Table 6 Specific parameters of calcareous sand

ρ/ (g·cm^-3)	G/GPa	K/GPa	a₀/ 10¹⁰Pa²	a₁/ 10⁵Pa²	a₂/ 10^-1
1.44	0.2967	2.34	2.94	4.1477	2.451

图13 试验与模拟产生的压力波形对比

Fig.13 Comparison of pressure waveforms generated by test and simulation

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