地场温度对湿喷桩成桩质量影响的试验研究

Experimental Study on Effect of Field Temperature on Quality of Wet Jetting Piles

为探索地场温度对湿喷桩戍桩质量的影响,自行研制了地场温度现场测试系统,并开发了湿喷桩大型室内相似模型试验系统,研究了湿喷桩桩长范围内地场温度的季节性变化规律和地场温度对湿喷桩强度的影响规律。结果表明:地基16 m范围内,地场温度以年为周期变化于12～20℃之间,气温是控制地场温度分布规律变化的主要因素,气温大于20℃时,地场温度随深度呈规则衰减趋势,在12-14 m处趋于恒定;气温小于20℃时,地场温度随深度先增加然后递减,在12～14m处趋于恒定,拐点深度约为7 m;地场温度变化对浅部湿喷桩强度存在较大影响,而7 m以下,地场温度对湿喷桩强度影响较小,不同季节下湿喷桩强度差异不足3%。由此可见,地场温度是影响湿喷桩强度变化的重要因素,合理选择施工时间,可以提高湿喷桩成桩质量。

In order to explore the effect of field temperature on the Wet Jetting Piles （WJP） quality, the field temperature testing system is developed to monitor the characteristics of field temperature＇ s distributing and changing, and the indoor model of WJP experimental system is developed simultaneously to test the effect of field temperature on the pile＇ s strength. The results of study indicat that the field temperature changes between 12 ℃ and 20 ℃ during one year within foundation depths of 16 m, and the air temperature is the key factor inducing the field temperature＇ s changing. When the air temperature is higher than 20 ℃, the field temperature became lower regularly with the depths declining.When the air temperature is lower than 20 ℃, the field temperature became higher among the foundation depths of 7 m, but the field temperature became lower below the foundation depths of 8 m and it is invariable at depth of 12 - 14 m during the year.When the foundation depths exceeded 12 - 14 m, the field temperature changing had a great effect on the strength of WJP within the foundation depths of 7 m.The strength of WJP with air temperature higher than 20 ℃ is 11% - 16% higher than that of the WJP air temperature lower than 20 ℃ .The WJP strength changed less than 3% under the WJP depths of 7 m.Thus the result shows that the field temperature is the important factor affecting the WJP strength, if the time of construction are selected between April and October, the quality of WJP can be improved.