盾构施工中通过不断地调整区压控制盾构姿态，然而在实际中如果将各分区压力参数设置差距太大会发生盾构姿态偏差反而加剧的情况。结合某城市地铁下穿江河段时遇过饱和软土发生沉降的案例，说明在盾构本身出现沉降偏差时，由于区压调整参数设置不合理，导致盾构推力不均匀反而加速盾构下沉的情况，对盾构推进的区压参数设置进行对比分析，并对盾构姿态持续下沉过程进行详细描述，分析区压过度调整对盾构姿态产生不利影响的原因。根据盾构推进压力对于管片的反作用力，从力学角度分析盾构姿态的调整是盾构区压设置的调整原理，阐述盾构姿态形成的受力状态是盾构自身偏转量与成型隧道管片受力不均呈现逆向偏差的结果。二者的偏转量是相反的，当调整区压设置导致成型隧道偏转量大于盾构自身偏转量时，盾构姿态将呈现越纠越偏的现象，即为区压过度调整。该结论指出盾构施工过程中姿态调整的误区，并对盾构施工推进参数设置的合理性提出见解。

In the shield construction, the shield attitude is controlled by continuously adjusting the zone pressure. However, if the gap between the pressure parameters of each zone is too large, the shield attitude deviation will be aggravated. Combined the case of the settlement in saturated soft soil when a city metro under passing the river section, it shows that when the settlement deviation of the shield itself occurs, the adjustment of the regional pressure parameters is unreasonable, resulting in uneven thrust of the shield and accelerated the sinking of the shield. Through comparative analysis of the regional pressure parameter settings of the shield propulsion, the continuous sinking process of the shield attitude is described in detail, and the reasons for the adverse effect of overadjustment of the regional pressure on the attitude of the shield are analyzed. According to the reactive force of the shield propulsion pressure on the segment, from the standpoint of mechanics, the adjustment of the shield attitude is the adjustment principle of the shield zone pressure setting. The forced state formed by the shield attitude presents the result of the reverse deviation, which caused by the shield deflection and the unevenness of tunnel segments. The deflection amount of the two is reversed and the adjustment of zone pressure causes that the deflection of the forming tunnel is larger than the deflection of the shield itself, and the shield attitude will be more deviated and the zone pressure is excessively adjusted. The conclusion points out the misunderstanding of attitude adjustment during the shield construction, and provides insights into the rationality of the setting of propulsion parameters for shield construction.